What Is Passion Flower Good For?

Passion flower (Passiflora Spp.), also known as passion fruit, egg fruit, native to southern Brazil, Paraguay and northern Argentina, is a perennial herbaceous vine climber belonging to the genus Passiflora (Passiflora L.), Passifloraceae. Passiflora is highly adaptable and has been planted in the South Pacific, central America, the Middle East, the Mediterranean and Southeast Asia, and is also cultivated in Taiwan, Fujian, Guangdong, Guangxi, Yunnan, Guizhou and other places in China. Cultivated varieties mainly include yellow-fruited passion flower, purple-fruited passion flower and their hybrids. Passiflora fruits are round or ellipsoidal, with purple or yellow skin at maturity, 5-8 cm in diameter, and are rich in vitamins, minerals, dietary fiber, and other nutrients[1-2] .

In addition to vitamins, minerals, dietary fiber and other nutrients, passion fruit contains a large number of biologically active substances, such as flavonoids[3], polysaccharides[4], alkaloids[5], carotenoids[6], cyanogenic glycosides[7] and so on. At the same time, passion flower fruit extract has the physiological functions of anxiolytic, antioxidant, anti-inflammatory, antimicrobial, anti-bacterial, and hypotensive, which can reduce preoperative anxiety, knee osteoarthritis, and type 2 diabetes mellitus. The research progress on the bioactive components and physiological functions of passion flower fruit is summarized for the reference of related researchers.

1 Main nutrients of passion flower fruit

In passion flower fruits, the pericarp accounts for 50%~55% of the fresh fruit weight, pulp accounts for 42.5%~34% of the fresh fruit weight, and seeds account for 7.5%~11.0%. Passiflora is rich in nutrients, and different parts of the fruit contain different nutrients. The content of protein and fat in passion flower pericarp is low, but the content of carbohydrates is very high, more than 50%, pectin and crude fiber are the main carbohydrates in passion flower pericarp, accounting for 12.5% and 22.1% of the fresh fruit weight, respectively[15] . Passiflora fruit pulp contains 17 kinds of amino acids required by the human body, 5 kinds of essential trace elements (Fe, Cu, Mn, Zn, Se), and is also rich in soluble sugar, total acid, protein, and VC[16] .

Passiflora seeds are rich in fatty acids, protein and fiber. The oil content of the whole seed reaches 21.7%-29.2%, and the unsaturated fatty acid content is over 80%, mainly linoleic acid and oleic acid, of which the essential fatty acid - linoleic acid content is over 72%, and the wholesome protein content of the whole seed is over 20%, which is second only to soybean in protein content among the plants, and the insoluble cellulose contained in every 100 g of the seed is 64.1 g[17-18] .

2 The main bioactive components of passion fruit

2.1 Flavonoids

Flavonoids are a class of secondary metabolites widely found in plants, the basic carbon framework contains two phenolic hydroxyl benzene rings (A-ring and B-ring) and a heterocyclic ring containing three carbon atoms, forming the structure of C6-C3-C6, which is a series of polyphenolic compounds[19] . Numerous studies have shown that flavonoids have a variety of biological activities such as anticancer, antioxidant, anti-inflammatory, prevention of cardiovascular diseases, anti-bacterial, anti-viral, and anthelmintic[20] . Passion flower fruits are rich in flavonoids. Currently, the research on flavonoids in passion flower mainly focuses on the analysis of flavonoid content and species.

Zeraik et al[21] found that the total flavonoid content of passion flower pulp (0.16 mg/mL) was comparable to that of orange juice (0.20 mg/mL) and sugarcane juice (0.24 mg/mL), and is a potential natural source of flavonoids. Simirgiotis et al.[3] showed that the flavonoid content in the skin (140.17 ± 4.2 mg/100 g DW) was 1.81 times higher than that in the pulp (77.16 ± 8.4 mg/100 g DW), and the results of high-performance liquid chromatography with diode array detector (HPLC-DAD) and liquid chromatography-mass spectrometry (HPLC-MS) showed that the flavonoids content in the skin (140.17 ± 4.2 mg/100 g DW) was 1.81 times higher than that in the pulp (77.16 ± 8.4 mg/100 g DW).

In addition, the results of HPLC-DAD and HPLC-MS showed that the flavonoids in the peel and pulp of passion flower were different, with 30 flavonoids in the peel and 15 flavonoids in the pulp, of which 15 of the 30 flavonoids in the peel were detected in the peel only, and of the 15 flavonoids in the pulp, one flavonoid was present in the pulp only. García-Ruiz[22] et al. identified 18 flavonoids, including 9 flavanetriol monomers and 9 proanthocyanidins, 9 flavanone-triol monomers and 9 proanthocyanidins, and 1 flavanone-triol monomer and 1 proanthocyanidin in the fruit pulp of Passiflora mollissima (Kunth) L.H. Bailey, by using reversed-liquid chromatography (RP-LC), HPLC, and HPLC-MS techniques. Among them, 9 flavanetriol monomers and 9 proanthocyanidins were identified, and the contents of flavonoids-triol monomers and proanthocyanidins accounted for 59.4% and 40.6% respectively. It can be seen that the flavonoids in Passiflora fruits are not only rich in content, but also diverse, and the flavonoids in different parts of the fruit differed significantly.

2.2 Carotenoids

Carotenoids are a kind of organic pigments, widely found in plants and algae. Epidemiological studies have found that carotenoids may reduce the risk of chronic diseases such as type 2 diabetes, cardiovascular disease, cancer and age-related macular degeneration[23] . Significant differences in carotenoids were found among different passion flower species and varieties.

Wondracek et al.[24] studied the carotenoids in different species and varieties of passionfruit and found that P. edulis had the most variety of carotenoids in the pulp, including neoxanthin, zeaxanthin, cis-xanthin, epoxidized zeaxanthin, lutein, zeaxanthin, β-cryptoxanthin, prenatriuretic lycopene, poli-cis-carotene, cis-ζ-carotene, trans-ζ-carotene, and β-cryptoxanthin, and the most abundant carotenoids in P. edulis. There were 13 species of carotenoids including trans-ζ-carotene, trans-β-carotene, 13-cis-β-carotene and hexahydroxy lycopene, followed by 7 species of Passiflora setacea, 5 species of Passiflora cincinnata, and the least carotenoids in the pulp of Passiflora nitida, which were only trans-β-carotene, epoxidized zeaxanthin and 2 species of epoxidized zeaxanthin.

The least amount of carotenoids in the flesh of Passiflora nitida was only trans-β-carotene and epoxidized zeaxanthin. Comparative analysis of the carotenoids in four different varieties of Passiflora edulis showed that there were significant differences in carotenoids among Passiflora edulis varieties. The main carotenoid in Passiflora edulis comerc b was trans-β-carotene, and the main carotenoid in Passiflora edulis comerc a was trans-ζ-carotene, while the main carotenoid in Passiflora edulis am native and Passiflora edulis ro native was cis-ζ-carotene.

The carotenoid content of Passiflora edulis am native and Passiflora edulis ro native differed significantly from each other, in addition to the carotenoid species. Wang Qinfei et al.[25] found that the lutein and β-carotene contents of purple-fruited, yellow-fruited and double-flowered passionfruit showed a trend of double-flowered passionfruit ＞ yellow-fruited passionfruit ＞ purple-fruited passionfruit. In addition, the carotenoids in passion flower are also affected by the cultivation method. Pertuzatti et al. [26] analyzed the carotenoids in conventional and organic passionfruit, and found that the carotenoid content of conventional passionfruit was nearly twice as much as that of organic passionfruit, but the main carotenoid was β-cryptoxanthin in the two types of passionfruit. However, the main carotenoid in both of them is β-cryptoxanthin. In conclusion, it can be seen that the carotenoids in passion fruit are not only related to the species and varieties, but also greatly affected by the cultivation method.

2.3 Plant polysaccharides

Plant polysaccharides are a kind of natural macromolecule substances, consisting of many identical or different monosaccharides with α- or β-glycosidic bonds, which are commonly found in the plant kingdom[27] . Modern medical research has shown that plant polysaccharides have biological activities such as antioxidant, antitumor, immunomodulatory, antibacterial, antiviral, hypoglycemic, hypolipidemic and so on[28] . The content of polysaccharides in passion flower pericarp and seeds is very rich, and the non-starch polysaccharides in the pericarp cell wall are as high as 80% (w/w), of which 42% are fibrillin, 25% are pectin, and 12% are hemicellulose[4] . Pectin and cellulose are important polysaccharides in Passiflora fruits, and animal experiments have shown that oral administration of cellulose from Passiflora pericarp can reduce blood glucose, triglyceride, cholesterol, insulin, and glucagon, and can be used for the treatment of diabetes mellitus[29] .

Animal studies have also shown that oral administration of passion flower pectin can lower blood glucose and triglyceride levels, reduce edema and myeloperoxidase release, and significantly reduce neutrophil permeability, tumor necrosis factor α, and inducible nitric oxide synthase production in diabetic rats, which are anti-inflammatory properties of passion flower pectin that may make it a therapeutic agent for type 2 diabetes[30] . In addition to the study of the biological activity of passionflower polysaccharides, the extraction method of passionflower polysaccharides is also the focus of research. Studies have shown that the polysaccharide fractions in the polysaccharide extracts from different extraction methods are different.

Silva et al[31] found that the main galacturonic acid in the hot water extract of Passiflora officinalis, in addition to small amounts of arabinose, glucose, rhamnose, mannose, alginate, xylose and ribose. Klinchongkon et al[32] found that polygalacturonic acid was the main polysaccharide component in the subcritical aqueous extract of passion flower pericarp using subcritical aqueous extraction technique, accounting for 65% of the polysaccharide content. In conclusion, pectin and cellulose are important polysaccharides in passion fruit and have some therapeutic effects on type 2 diabetes mellitus. In addition, the polysaccharide extracts obtained by different extraction methods contained different components of polysaccharides, and further studies are needed to determine whether such differences may cause differences in the biological activities of the polysaccharide extracts.

2.4 Cyanogenic glycosides

Cyanogenic glycosides are non-toxic organic compounds, but they produce toxic hydrogen cyanide when decomposed by enzymes. Passiflora fruits contain cyanogenic glycosides in the pericarp and juice cells except seeds, and the concentration is highest in young fruits, and the content of cyanogenic glycosides in the pericarp and juice cells decreases with the ripening of the fruits, and the content of cyanogenic glycosides in the fruits reaches the lowest level after ripening, so that consumption of ripe passionfruit will not be poisonous to the human body[7] .

In addition, there were significant differences in the types and contents of cyanogenic glycosides in the rind and pulp of Passiflora, and the main cyanogenic glycosides of the rind were black cherry glycoside, which only existed in the rind, whereas the main cyanogenic glycosides of the pulp were bitter amygdalin and mandelonitrile rhamnopyranosyl β-d-glucopyranosides, which existed only in the pulp. Mandelonitrile rhamnopyranosyl β-d-glucopyranosides, the main cyanogenic glycoside of the fruit pulp, was not detected in the pericarp, and although phenylacetonitrile glucopyranosides were detected in both the pericarp and the fruit pulp, the amount of phenylacetonitrile glucopyranosides in the pericarp was about 40 times higher than that in the flesh of the fruit[33] . Although cyanogenic glycosides are non-toxic and no toxicity has been reported in passion flower, it is necessary to reduce the intake of cyanogenic glycosides to minimize the risk of toxicity. Therefore, fully ripened passion flower fruits should be selected for consumption.

2.5 Alkaloids

Alkaloids are a group of nitrogenous natural organic compounds that are mainly found in the plant kingdom, but can also be synthesized in some bacteria, fungi and animals. Alkaloids have various medicinal activities, such as antimalarial, antiasthmatic, anticancer, antidysrhythmic, antimicrobial, antiviral, hypotensive, etc.[34-36] . There are many studies on the leaf alkaloids of Passiflora, but few studies on the fruit alkaloids.

Although the alkaloids of Passiflora edulis were reported in 1968, it was not until 1975 that Lutomski et al [37] isolated four alkaloids from the pulp of purple-fruited Passiflora edulis Sims and yellow-fruited Passiflora edulis f. flavicarpa by thin-layer chromatography. Four alkaloids were isolated from the pulp of Passiflora edulis (Passiflora edulis Sims) and Passiflora flavicarpa (Passiflora edulis f. flavicarpa): harmonine, dehydrocamptothecin, harmanol, and dihydrocamptothecin. In 2014, Pereira et al.[5] identified two alkaloids, harmaline and dehydrocamptothecin, from the pulp and seeds of Passiflora edulis f. flavicarpa (Passiflora edulis f. flavicarpa O. Degener) by using double stir bar solid phase extraction and liquid chromatography with fluorescence detection. Although the research on alkaloids of passionflower started earlier, the progress of related studies has been slow, probably due to the complex composition of samples such as fruit pulp and fruit juice, which makes it difficult to study. With the further comprehensive development and utilization of passionflower, more research on passionflower alkaloids is necessary in view of the safety of food and cosmetic products containing passionflower ingredients.

In addition to flavonoids, carotenoids, phytopolysaccharides, alkaloids and cyanogenic glycosides, passion flower fruits also contain some other bioactive components, such as betulinol, anthocyanosides, furazone, coumarin, myristic acid, palmitic acid, piperine and dihydroxypeppermint, etc.[38-40] . With the exception of paclitaxel, which has been shown to inhibit melanogen production in dermal cells and promote collagen production, and can slow down the aging of human skin [41], there is no direct evidence for the bioactivity of other substances, and their bioactivities need to be further investigated. Passiflora is rich in bioactive substances, which should be vigorously researched, developed and utilized.

3 Main physiological functions of passion fruit

3.1 Anxiolytic effect

In South America, several species of Passiflora are widely used as traditional medicines for anxiolytic and tranquilizing effects. Barbosa et al[42] , after injecting Passiflora alata and Passiflora edulis aqueous extracts intraperitoneally into male Wistar rats, performed the maze test, obstacle avoidance test, and open-space adaptation test on Wistar rats, and found that the aqueous extracts had a sedative effect similar to that of Valium, and that the aqueous extracts had an antianxiety effect similar to that of Valium. It was found that the aqueous extracts of Passiflora stems and wings and Eucalyptus citriodora had a sedative effect similar to that of Valium and did not disrupt the memory process of rats as Valium did.

Otify[43] et al. further showed that passionflower extract significantly reduced the locomotion and increased the concentration of amino butyric acid (GABA) neurotransmitter in mice, suggesting that passionflower extract acts on the GABA system, and exerts anxiolytic and tranquilizing effects by affecting the receptors of GABAA and GABAB and the binding effect of GABA. In addition, although the substances in the ethanol, chloroform, ethyl acetate and butanol extracts of passionflower were different, there was no significant difference in their anxiolytic effects, suggesting that the anxiolytic effects of passionflower extracts are the result of synergistic effects of multiple active ingredients rather than the activity of a particular substance. In clinical trials, it was found that the administration of pink passion flower (Passiflora incarnate) before surgical operations could effectively reduce patients' anxiety, and did not adversely affect the recovery of psychological and motor nerves during the recovery period of anesthesia[12] . The above results suggest that Passiflora incarnate has a good anxiolytic effect, and has a good performance in clinical trials, and its anxiolytic mechanism is related to the GABA system, the receptors of GABAA and GABAB, and the binding effect of GABA.

3.2 Antioxidant effects

Epidemiologic evidence suggests that many human diseases are caused by free radical damage to lipids, proteins, and DNA in the body, and that consumption of foods or substances with antioxidant effects may reduce the incidence of disease and human mortality[44] . Lourith et al.[45] showed that the antioxidant capacity of passion flower extract was related to the extraction solvent, and the antioxidant capacity of the ethyl acetate phase was significantly higher than that of the aqueous phase. It was also found that the content of polyphenols in the ethyl acetate phase was significantly higher than that in the aqueous phase, and chlorogenic acid, rosemarinic acid and quercetin existed in large quantities in the ethyl acetate phase, whereas crotonic acid and gallic acid existed in large quantities in the aqueous phase, which indicated that polyphenols, chlorogenic acid, rosemarinic acid and quercetin were the main antioxidant activities of Passiflora officinalis.

Contreras-Calder6n et al.[8] found that the ABTS radical scavenging and FRAP iron ion antioxidant activities of the edible parts of Passiflora tarminiana and Passiflora mollisima were significantly higher than those of cashews, guava apples and Brazilian guava. The antioxidant capacity of the edible parts of 23 tropical fruits was significantly higher than that of cashews, guava apples, and Brazilian guavas, and this antioxidant capacity was highly correlated with their polyphenol content.

García-Ruiz et al.[22] and others found that the DPPH radical scavenging and ORAC radical uptake capacities of lyophilized and dry powder capsule samples of Passiflora mollissima (Kunth) L.H. Bailey fruit pulp were significantly higher than those of other Latin American fruits, such as Morinda citrifolia, Lantern fruit, Acai berry, Cassia, etc. The antioxidant capacities of these samples were significantly higher than those of edible parts of 23 tropical fruits, such as cashew, guava apple, Brazilian guava, etc. This antioxidant capacity was highly correlated with their polyphenol contents, The DPPH radical scavenging and ORAC oxidative radical uptake capacities were significantly higher than those of other Latin American fruits, such as Morinda citrifolia, Lantern fruit, Acai berry, and Cassia, and were positively correlated with flavonoids and carotenoids. The above results indicated that passion flower has good antioxidant activity and is a natural source of antioxidants. The antioxidant activity of passion flower may be related to the antioxidant effects of polyphenols, flavonoids, carotenoids and other organic acids.

3.3 Anti-inflammatory effects

Clinical trials have shown that the use of passionflower pericarp extract can reduce inflammation in the knee joint, inhibit matrix metalloproteinase activity, prevent further development of arthritis and joint degeneration, and improve the symptoms of knee osteoarthritis, including pain and stiffness of the knee joint[13] . Silva et al.[30] showed that passion fruit pectin significantly reduced the release of myeloperoxidase from human neutrophils, reduced keratan-induced paw edema like the anti-inflammatory drug indomethacin, significantly reduced the migration of leukocytes in the paws of keratan-induced inflammation, and reduced the levels of α-tumor necrosis factor (TNF-α) and inducible nitric oxide synthase (iNOS) to a certain extent. The results suggest that passion flower fruit can reduce the migration of leukocytes in the paws of mice with inflammation.

These results suggest that passion fruit pectin has anti-inflammatory activity. Further studies showed that the pre-peritoneal injection of passion flower pericarp polysaccharide (PFPe) in mice significantly inhibited keratan-induced edema, reduced edema induced by 48/80 compounds, histamine, serotonin, and prostaglandin E2, and increased vascular permeability induced by 48/80 compounds, and significantly reduced myeloperoxidase activity, malondialdehyde and glutathione concentrations, and interleukin-1β levels [46]. In addition, PFPe significantly reduced myeloperoxidase activity, malondialdehyde and glutathione concentrations, and interleukin-1β levels [46]. These findings suggest that passionflower polysaccharides may play an anti-inflammatory role by regulating the synthesis and release of histamine and serotonin, decreasing neutrophil migration, lowering interleukin-1β levels, and scavenging free radicals.

3.4 Lowering blood pressure

Hypertension is one of the most dangerous factors in cardiovascular and cerebrovascular diseases. Clinical experiments have shown that after 16 weeks of continuous oral administration of 220 mg of Passiflora vulgaris pericarp extract to patients with type 2 diabetes mellitus, the systolic blood pressure of the patients decreased significantly, but there was no significant change in the diastolic blood pressure[11] . Lewis et al[47] found that the feeding of passion flower peel extract significantly reduced mean arterial pressure, arterial systolic blood pressure, arterial diastolic blood pressure and heart rate in spontaneously hypertensive rats at doses higher than 50 mg/kg. Further isolation of the active components of passion flower peel extract revealed that Edulilic Acids and Anthocyanins were the main hypotensive active components of passion flower peel extract.

Moriguchi et al[48] found that passionflower peel extract lowered blood pressure in spontaneously hypertensive rats by decreasing the concentration of nitric oxide in the blood. Konta et al.[49] found that feeding passion fruit pulp to spontaneously hypertensive rats significantly reduced arterial systolic blood pressure, increased blood glutathione levels, and lowered blood thiobarbituric reactant concentrations, suggesting that passion fruit pulp may lower arterial blood pressure by enhancing the antioxidant capacity of the blood. The analysis of renal function parameters and the mutation frequency of micronuclei in bone marrow cells showed that passion fruit pulp was not nephrotoxic and mutagenic, and was safe for consumption. These results suggest that passionflower has significant hypotensive activity and is safe to consume, and that it may lower blood pressure in two ways: by increasing the antioxidant capacity of the blood and by lowering the concentration of nitric oxide.

3.5 Treatment of diabetes

Diabetes mellitus is an endocrine disease that is considered to be the fourth leading cause of death worldwide. Oral administration of passionflower pericarp fiber to rats with tetracycline-induced diabetes mellitus significantly lowered blood glucose concentration in diabetic rats, and the higher the dose of oral administration of passionflower pericarp fiber, the greater the decrease in blood glucose, and oral administration of passionflower pericarp fiber reduced triglyceride and very-low-density-lipoprotein levels in the presence of low insulin and lipotropic factor[29] . In further study, it was found that in diabetic rats fed with passionflower pericarp powder, blood glucose was reduced and liver glycogen was significantly increased, suggesting that passionflower pericarp powder can promote the conversion of blood glucose to liver glycogen to regulate blood glucose concentration in diabetic rats[50] .

In addition, oral administration of methanolic extract of passion flower seeds to rats with tetracycline-induced diabetes not only reduced blood glucose concentration, but also lowered the concentrations of blood lipids such as triglyceride, low density lipoprotein (LDL), very low density lipoprotein (VLDL), and total cholesterol, and increased the levels of high density lipoprotein (HDL)[51] . Clinical trials have shown that oral administration of passion flower pericarp powder reduced fasting blood glucose and glycosylated hemoglobin concentrations, decreased insulin resistance, and increased insulin β-cell secretion in type 2 diabetes mellitus patients[14] . The above results suggest that passionflower may be able to regulate blood glucose and lipid concentrations by improving insulin sensitivity and increasing the secretion capacity of insulin β-cells, thus achieving the therapeutic effect of diabetes mellitus.

3.6 Anti-skin aging

Skin aging is caused by the accumulation of oxidative stress and inflammation. Inflammation is accompanied by increased levels of pro-inflammatory cytokines, which cause damage to the extracellular matrix and dermal-epidermal junctions, leading to a loss of elasticity in the skin, and these changes lead to the formation of wrinkles. Martin et al.[52] found that oil concentrate from Passiflora vulgaris could reduce oxidative damage caused by ultraviolet rays by decreasing the production of inflammatory factors in keratinocytes, increasing the expression of genes for catalase, quinone oxidoreductase 1, mitochondrial peptidomethionate sulfoxide reductase, and glutathione synthetase in fibroblasts, and stimulating the expression of genes for collagens I, IV, and VII, elastin, hyaluronan synthase 2, and collagen I, IV, and VII, and elastin. Hyaluronan synthase 2 gene expression increases hyaluronic acid production and restores the expression of elastin, collagen III and IV, and basement membrane glycan genes, among other mechanisms, to slow down the development of wrinkles.

Bravo[53] et al. showed that the extract of whole fruit of Passiflora vulgaris could inhibit the activities of collagenase, elastase, hyaluronidase, tyrosinase and other enzymes related to skin aging to different degrees. Matsui et al.[41] found that the extract of passion flower seed inhibited melanogen production and promoted collagen production in dermal cells when human melanoma cells and human dermal fibroblasts were cultured in a medium containing passion flower seed extract. These results suggest that passionflower extract has a significant effect on the delay of skin aging by regulating the expression of related genes, enhancing free radical scavenging, reducing inflammation, and regulating the synthesis of collagen, etc. The results also suggest that passionflower extract has a significant effect on the delay of skin aging.

4 Development prospect and outlook

With the development of society and the improvement of people's health consciousness, people are paying more and more attention to health food and health products. Passion flower is not only rich in nutrients, but also rich in a variety of biologically active components, and possesses a variety of physiological functions that are beneficial to the human body, and has a very good health care effect, which is becoming more and more popular among consumers. Although some progress has been made in the development and utilization of passion flower, there are still some problems.

In the international market, passion flower is mainly consumed in the form of passion flower juice. During the processing of passionfruit juice, a large amount of pomace is generated, and the disposal of pomace will increase the cost of enterprises and environmental pressure, so a large number of studies on passionfruit peel and pomace have been carried out. Therefore, a lot of studies on passion fruit peel and pomace have been carried out. Therefore, there are a lot of literature reports on the analysis and isolation of the bioactive components of the peel and pomace, as well as their physiological activities, while there are fewer studies on the pulp and fruit juice. Therefore, further research on the bioactive substances and physiological activities of passion fruit pulp and juice can help to promote the consumption of passion fruit and the development of passion fruit industry.

Although some progress has been made in the study of bioactive substances and physiological activities in passion flower peel and pomace, the physiological activity studies are mostly based on the complexes extracted from passion flower, but it is not possible to determine which type of substance has which physiological activity, and its mechanism of action is not clear. Further research on bioactive substances and their mechanisms of action will be beneficial to the development of passion flower products.

Passionfruit juice has been consumed since the 1950s and 1960s, but until now there have been few passionfruit products other than fresh fruit and juice. Although in Brazil and other countries, the dried passion fruit peel powder is used to assist in the treatment of diabetes and to replace flour to make bread, in China, there are also products such as passion fruit jam and dried fruit, but there is a lack of deep-processed products. Passiflora fruits are not resistant to storage and are easily wrinkled, resulting in a decline in the commercialization of fresh fruits, and juice processing is one of the effective ways to solve the storage problem of passionfruit. If the pomace produced by juice processing can be fully utilized, it will have far-reaching practical significance for sustainable development and green development. Therefore, to strengthen the research on various bioactive substances and their functioning mechanism of passion flower, and to promote the development and application of deep processing of passion flower, has a broad prospect and very important economic value.

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