Advances in Research on Chemical Constituents and Their Biological Activities of the Genus Actinidia

Jin-Tao Ma ·Da-Wei Li ·Ji-Kai Liu ·Juan He

Abstract Kiwi, a fruit from plants of the genus Actinidia, is one of the famous fruits with thousand years of edible history.In the past twenty years, a great deal of research has been done on the chemical constituents of the Actinidia species.A large number of secondary metabolites including triterpenoids, flavonoids, phenols, etc.have been identifi ed from diff erents parts of Actinidia plants, which exhibited signifi cant in vitro and in vivo pharmacological activities including anticancer, anti-infl ammatory, neuroprotective, anti-oxidative, anti-bacterial, and anti-diabetic activities.In order to fully understand the chemical components and biological activities of Actinidia plants, and to improve their further research, development and utilization, this review summarizes the compounds extracted from diff erent parts of Actinidia plants since 1959 to 2020, classifi es the types of constituents, reports on the pharmacological activities of relative compounds and medicinal potentials.

Keywords Actinidia chemical constituents·Isolation·Biological activities

1 Introduction

With the development of natural product research, a huge number of chemical constituents have been identifi ed from natural resources.There is no doubt that the research on the chemical composition of fruits, including trace elements, has greatly improved the application prospects of these fruits.With no exception, it is the same to kiwifruit, one of the most prestigious fruits with a long history of eating [1,2].Kiwi belongs to plants of the genusActinidiacomprising more than 70 species around the world [3].Some of these plants are proven to have a wide range of medicinal activities.For example,A.valvata, whose root is known as ‘‘Mao-Ren-Shen” in traditional Chinese medicine, exhibits antitumor and anti-infl ammatory activities and has been used for the treatment of hepatoma, lung carcinoma and myeloma for a long time [4,5].The roots ofA.chinensisPlanch, called “Teng-Li-Gen” usually, were used as a traditional Chinese medicine for the treatment of various cancers, such as esophagus cancer, liver cancer, and gastric cancer [6].In the past two decades, great research had been accomplished about exploring the chemical composition ofActinidiaplants.These studies have greatly promoted the understanding of the chemical components and functions of theActinidiaplant.According to literature survey, 12Actinidiaspecies includingA.valvata,A.chinensis, A.argute,A.polygama,A.kolomikta,A.eriantha,A.macrosperma,A.deliciosa,A.chrysantha,A.rufa,A.indochinensis, andA.valvatawere reported for their natural products.This review systematically summarizes the chemical components and their biological activities from diff erent parts of 12Actinidiaspecies from 1959 to 2020.According to structure types, a total of 325 molecules have been collected including terpeniods, phenols, and other small groups (Fig. 1).Names and isolation information were listed in the tables, while the biological activities of the extracts or compounds were discussed in the text.

Fig.1 Constituents proportion of 12 Actinidia plants

2 Chemical Constituents

2.1 Terpenoids

In recent years, a large number of terpenoids were isolated from manyActinidiaspecies.Among them, triterpenes account for the vast majority that are mainly composed by several normal frameworks including ursane-type, oleanane-type, and lupane-type.Of the total 325 compounds in this review, 104 are triterpenoids.From the literature review, ursolic acids and their saponins are undoubtedly the most abundant inActinidiaspecies.

2.1.1 Ursane Triterpenoids

Ursane-type triterpenes are characterized of ursolic acid and its saponins, possessing a 6/6/6/6/6-fused carbon skeleton.A total of 76 ursane-type triterpenoids ( 1– 76) have been identifi ed from plants of the genusActinidia(Fig. 2, Table 1).Ursolic acid (3β-Hydroxyurs-12-en-28-oic acid 1) [7], is one of the most frequently obtained compound in many kinds of kiwifruit plants with unique flavor.Great attention had been paid on biological activities about ursolic acid, attracting much interest in recent years.Ursolic acid exhibits diff erent pharmacological activities, including anti-cancer, amylolytic enzyme inhibitors, cytotoxicity, downregulating thymic stromal lymphopoietin and others [7– 11].

Compound 30 (3β-O-acetylursolic acid) was isolated from the fruit galls ofA.polygamaand the structure was elucidated on the basis of chemical and spectral evidence.It was reported to be a mixed-type protein tyrosine phosphatase 1B (PTP1B) inhibitor with an IC50value of 4.8 ± 0.5μΜ [23,24].Isolation of the antiviral active ingredient ofA.chinensisroot bark gave fupenzic acid 40, which showed moderate inactivity under the concentration of 100 μg/mL [25].Callus tissue from the stems ofA.arguta(Actinidiaceae) produced three ursane-type triterpenes including ursolaldehyde 41,α-amyrin 42, and uvaol 43 [26].Of them, compound 43 showed anti-infl ammatory, anticancer, and wound healing activities [27– 29].Antiinfl ammatory properties of 43 on DSS-induced colitis and LPS-stimulated macrophages have been explored detailly and completely.It showed excellent potential of NO production inhibition.It could attenuate disease activity index (DAI), colon shortening, colon injury, and colonic myeloperoxidase activity in DSS-induced colitis mice.What’s more, studies on LPS challenged murine macrophage RAW246.7 cells also revealed that uvaol reduces mRNA expression and production of pro-infl ammatory cytokines and mediators.These results indicating that uvaol is a prospective anti-infl ammatory agent for colonic infl ammation [27].Guided by the hepatoprotective activity, the phytochemical study on the roots ofA.chinensisled to the isolation of two new compounds 2α,3β-dihydroxyurs-12-en-28,30-olide 46, 2α,3β,24-trihydroxyurs-12-en-28,30-olide 47 and 3β-hydroxyurs-12,18-dien-28-oic acid 50 [30].Compounds 52 -54 showed antifungal activity againstC.musaeat 3 μg/mL [31].A new compound 2α,3α,23,24 -tetrahydroxyursa-12,20(30)-dien-28-oic acid 55 was isolated from the roots ofA.chinensisPlanch.It exhibited moderate antitumor activities against fi ve human cancer cell lines (HepG2, A549, MCF-7, SK-OV-3, and HeLa) with IC 50 values of 19.62 ± 0.81, 18.86 ± 1.56, 45.94 ± 3.62, 62.41 ± 2.29, and 28.74 ± 1.07 μM, respectively [32].

Fig.2 Structures of ursane triterpenoids 1-76 from Actinidia plants

Fig.2 (continued)

Fig.2 (continued)

Fig.2 (continued)

Compounds 59 -63 are actinidic acid derivatives with a phenylpropanoid unit that were identifi ed as 3-O-transp-coumaroylasiatic acid 59, 23-O-trans-p-coumaroylasiatic acid 60, actiniargupene E 61, actiniargupene F 62, and actiniargupene G 63 from the leaves ofA.arguta.All the compounds showed inhibitory eff ects onα-glucosidase activity.Among them compound 59 showed most potentially inhibitory activity onα-glucosidase with an IC50of 81.3 ± 2.7 μM, equal to that of the positive control (acarbose, 72.8 ± 3.1 μM) [33].The structure–activity relationship suggested that triterpenoids with a phenylpropanoid moiety exhibited more potent eff ects than those without such a unit [34].Compound 71 showed potent cytotoxic activity against human SKVO3 and TPC-1 cancer cell lines with IC50values of 10.99 and 14.34 μM, respectively [19,35].Compound 74 exhibited moderate cytotoxic activity against BEL-7402 and SMMC-7721 tumor cell lines [22].Compounds 75 and 76 were isolated from roots ofA.valvataDunn.They exhibited moderate cytotoxic activity in vitro against BEL-7402 and SMMC-7721 tumor cell line [36].

2.1.2 Oleanane Triterpenoids

Oleanane-type triterpenoids also possessed a 6/6/6/6/6 pentacyclic carbon skeleton.Unlike ursane triterpenes, oleanane-type triterpenoids have two methyl groups at the C-20 position instead of each one at the C-19 and C-20, respectively.So far, a total of 24 oleanane-type triterpenoids have been identifi ed fromActinidiaplants ( 77 -100, Fig. 3, Table 2).The most representative compound is oleanolic acid 77.It was found from callus tissue from the stems ofA.arguta, together with 2α,3β-dihydroxyolean-12-en-28-oicacid 78 [26].Oleanolic acid 77 is abundant in nature and exhibits a wide range of biological activities including anti-infl ammatory [54], anti-hypertension [55], anti-tumor [56,57], neuroprotection [58], and anti-cholesterol activities [59].Oleanolic acid was performed to test the eff ect on apoptosis and autophagy of SMMC-7721 Hepatoma cells.It can signifi cantly inhibit the growth of liver cancer SMMC-7721 cells and induce autophagy and apoptosis [57].Compound 78 also showed anti-tumor and anti-infl ammatory activities [60,61].Lim et al.have demonstrated that 78 showed very strong anti-tumor-promoting activity with an IC50of 0.1 mg/mL [60].

Table 1 Information of ursane triterpenoids from Actinidia plants

Table 1 (continued)

Table 1 (continued)

Bioassay- and 1 H NMR-guided fractionation of the methanol extract aff orded two oleanolic acids of 2α,3β,23-trihydroxyolean-12-en-28-oic acid 80 and 2α,3α,24-trihydroxyolean-12-en-28-oic acid 81, showing antifungal activity againstC.musaeat 3 μg/mL [31].The EtOAc extract of the roots ofA.erianthaBenth exhibited potent growth inhibitory activity against SGC7901 cells, CNE2 cells and HUVECs cells.From which, compound 87 (3β,23,24-trihydroxyl-12-oleanen-28-oic acid) was identifi ed [62].Compound 88 was extracted from the roots bark ofA.chinensis, which showed anti-viral activity [25].A new triterpenoid 12α-chloro-2α,3β,13β,23 -tetrahydroxyolean-28-oic acid-13-lactone 89 was extracted from the roots ofA.chinensisPlanch (Actinidiaceae).It was tested for cytochrome P450 (CYPs) enzyme inhibitory activity in later years, which could signifi cantly inhibit the catalytic activities of CYP3A4 to < 10% of its control activities [19,52].

3β-(2-Carboxybenzoyloxy) oleanolic acid 93 and spathodic acid-28-O-β- D-glucopyranoside 94 were extracted from the root bark ofA.chinensis.The anti-phytoviral activity test indicated that 94 showed potent activity on TMV, and CMV with inactivation eff ect of 46.67 ± 1.05, and 45.79 ± 2.23 (100 mg/L), compared to ningnanmycin with inactivation eff ect of 30.15 ± 1.16 and 27.18 ± 1.02 (100 mg/L) respectively [25].3β,23-Dihydroxy- -30-norolean-12,20(29)-dien-28-oic acid 98, 3β,23-dihydroxy-1-oxo-30-norolean-12,20(29)-dien-28-oic acid 99, and 2α,3α,23,24-tetrahydroxy-30-norolean-12,20(29)-dien-28-oicacid 100 are three one-carbon-degraded oleanane triterpenoids that were identifi ed fromA.chinensisRadix for the fi rst time [50].

2.1.3 Lupane Triterpenoids

Fig.3 Structures of oleanane triterpenoids 77-100 from Actinidia plants

Table 2 Information of oleanane triterpenoids from Actinidia plants

Lupane triterpenoids possess a 6/6/6/6/5-fused carbon skeleton.Compared with ursane and oleanane triterpenoids, the number of lupane triterpenoids in theActinidiaplants is much smaller, only four related compounds have been identifi ed ( 101-104, Fig. 4, Table 3).Three of them ( 101-103) were identifi ed from the rhizomes ofA.kolomikta[51].Betulinic acid 101 is one of the most representative compound of lupane triterpenes, it has been extensively studied in recent years based on the wide biological activities including anti-infl ammatory, antitumor, anti-HIV, anti-diabetic and antimalarial activities [68– 73].Much attention as a molecular target about protein tyrosine phosphatase 1B had been paid to the treatment of insulin resistance diseases because of its critical roles in negatively regulating insulin- and leptin-signaling cascades.Betulinic acid showed signifi cant PTP1B inhibitory activity, with IC50values of 3.5 μM [24].

Fig.4 Structures of lupane triterpenoids 101 -104 from Actinidia plants

2.1.4 Other Terpenoids

A total of 19 other terpenoids including iridoids, diterpenoids, and their glycosides have been found fromActinidiaplants ( 105 ? 123, Fig. 5, Table 4).None of these compounds have good biological activities, only compound 120 showed certain anti-angiogenesis activity [77].

2.2 Steroids

β-Sitosterol 124 is a very normal phytosterol almost distributed in all plants.Eight phytosterols have been obtained from theActinidiaplants ( 124 -131, Fig. 6, Table 5).Pharmacological studies on these steroids have demonstrated thatβ-sitosterol showed various bioactivities including anti-infl ammatory, anti-cancer, antimicrobial and anti-diabetic properties [81– 88].A study suggested thatβ-sitosterol may serve as a potential therapeutic in the treatment of acute organ damages [82].

In addition to phytosterols, seven normal ergosterols ( 132-137, Fig. 6, Table 5) were obtained from peel or rhizomes of kiwifruit plants.It is well known that ergosterols should be fungal products.Compounds 132-137 may be produced by fungal infected kiwifruit plants.

2.3 Phenol s

2.3.1 Catechins and Epicatechins

A total of 16 related compounds ( 139 -154) have been obtained from kiwifruit plants (Fig. 7, Table 6).Compounds 148 and 149 possessed a novel structure featuring with a pyrrolidin-2-one substituent at C-6 and C-8, respectively.Compounds 152 and 153 were two sulfur-containing catechins that was rare in nature.Pharmacological studies have revealed that (+)-catechin 139 and (?)-epi-catechin 140 showed nitric oxide inhibitory activity in LPS stimulated RAW 264.7 cell with IC50values of 26.61 and 25.30 μg/mL, respectively [53,91].Compound 147 showed moderate radical scavenging and antioxidant capabilities by measuring their capacity to scavenge DPPH and anion superoxide radical and to reduce a Mo(VI) salt [89].Two new flavan-3-ols, 6-(2-pyrrolidinone-5-yl)-(?)-epicatechin 148 and 8-(2-pyrrolidinone-5-yl)-(?)-epicatechin 149, as well as proanthocyanidin B-4 150, were isolated from an EtOAcsoluble extract of the roots ofA.arguta.The isolates were tested in vitro for their inhibitory activity on the formation of advanced glycation end products (AGEs).All of them exhibited signifi cant inhibitory activity against AGEs formation with IC50values ranging from 10.1 to 125.2 μM [92 ].

2.3.2 Flavones, Isofl avones, and Flavonols

A total of 48 flavone derivatives have been identifi ed from kiwifruit plants, most of which are glycosides ( 155 -202, Fig. 8, Table 7).Pharmacological studies indicated that these compounds, particularly kaempferol and its derivative, had a wide range of biological activities including antiproliferation, antioxidation, anti-infl ammation, anticancer, anti-free radical, and neuroprotection activities [96– 99].Kaempferol 157 was found to prevent neurotoxicity by several wayswhich was able to completely blockN-methyl-D-aspartate (NMDA)-induced neuronal toxicity and potently inhibited MAO (monoamine oxidase) with the IC50of 0.8 μM [99].Two novel flavonoids 171 and 172 were separated from the leaves ofA.valvataDunn.They exhibited dose-dependent activity in scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, superoxide anion radicals, and hydroxyl radicals, and inhibited lipid peroxidation of mouse liver homogenate in vitro [100].Compounds 178 [101] and 179 [102] were two new compounds obtained from the leaves ofA.kolomikta.The latter was screened for its protective eff ect on human erythrocytes against AAPH-induced hemolysis,which could slow the hemolysis induced by AAPH [102].Eerduna et al.evaluated the eff ects of compound 182 on acute myocardial infarction in rats, the groups treated with 182 showed a dose-dependent reduction in myocardial infarct size model, markedly inhibited the elevation of the activity of creatine kinase, troponin T level, and the content of malondialdehyde induced by AMI [103].Compound 182 also showed a capacity to increase the activities of superoxide dismutase, catalase, and endothelial nitric oxide synthase [104].Lim et al.tested the DPPH radical scavenging activity and nitric oxide production inhibitory activity in IFN-γ, LPS stimulated RAW 264.7 cell of quercetin 185, quercetin-3-O-β- D-glucoside 186, and quercetin 3-O-β- D-galactoside 193 with IC 50 value of 20.41, 18.23, and 30.46 μg/mL, respectively [91].

Table 3 Information of lupane triterpenoids from Actinidia Plants

Fig.5 Structures of other terpenoids 105 -123 from Actinidia plants

Table 4 Information of other triterpenoids from Actinidia plants

Fig.6 Structures of steroids 124-138 from Actinidia plants

Table 5 Information of steroids from Actinidia plants

2.3.3 Xanthones

Three xanthones were isolated from n-butyl alcohol fraction ofA.arguta(Sieb.& Zucc) Planch.ex Miq and identified as 2-β- D-glu-1,3,7-trihydrogen xanthone 203, 7-O-[β- D-xylose-(1 → 6)-β- D-glucopyranoside]-1,8-dihydroxy-3-methoxy xanthone 204, and 1-O-[β- D-xylose-(1 → 6)-β- D-glucopyranside] -8-hydroxy-3,7-dimethoxy xanthone 205 (Fig. 9, Table 8).They were isolated from this plant for the fi rst time [108].Compound 203 showed extensive biological activities, including inhibitingα-Glycosidase, NO production inhibition and NF-κB inhibition and PPAR activation [116,117].It has been demonstrated the inhibitory eff ects on NF-κB transcriptional activation in HepG2 cells stimulated with TNFαwith an IC50value of 0.85 ± 0.07 μM, which was more potent than the positive control of sulfasalazine (IC50= 0.9 μM) [118].

2.3.4 Anthocyanins

Five anthocyanins were obtained from the flesh of larger fruit ofA.deliciosaandA.chinensisand identifi ed as delphinidin 3-galactoside 206, cyanidin 3-galactoside 207, cyanidin 3-glucoside 208, delphinidin 3-[2-(xylosyl)galactoside] 209, and cyanidin 3-[2-(xylosyl)galactoside] 210, respectively (Fig. 9, Table 8) [119].Cyanidin 3-glucoside 208 exhibited a wide range of pharmacological activities including anti-infl ammatory, neuroprotective, anti-cancer, and antioxidant activities [120– 124].

Fig.7 Structures of catechins and epicatechins 139 -154 from Actinidia plants

Table 6 Information of catechins and epicatechins from Actinidia plants

2.3.5 Emodins

A total of nine emodin derivatives were obtained ( 211-219, Fig. 9, Table 8).Three emodin constituents were isolated from EtOAc fraction of the roots ofA.deliciosafor the fi rst time, and their structures were identifi ed to be aloe-emodin 211, 11-O-acetyl-aloe-emodin 212, and aloe-emodin 11-O-α- L-rhamno -pyranoside 213 [125].Compound 211 exhibited intriguing biological activities including infl ammatory, antifungal, and anticancer activity [126– 128].Lipoxygenases (LOXs) are potential treatment targets in a variety of infl ammatory conditions, enzyme kinetics showed that aloe emodin inhibited lipoxygenase competitively with an IC50of 29.49 μM [126].Compound 215 was reported to possess wide biological activities including anti-infl ammatory, neuroprotection, anti-cardiovascular andα-glucosidase inhibitory activity [129– 132].It exhibited potent inhibition of α-glucosidase with an IC 50 value of 19 ± 1 μM and lower cytotoxicity to the Caco-2 cell line [132].

2.3.6 Phenylpropionic Acids

A total of 38 phenylpropionic acid derivatives have been identifi ed from kiwifruit plants ( 220 -257.Fig. 10, Table 9), while most of them were glycosides or quinic acid derivatives.Phytochemical examination of the fruits ofA.argutaled to the isolation of two organic acids including caff eic acid 220 and caff eoyl-β- D-glucopyranoside 221, which were tested for their nitric oxide production inhibitory activity in LPS-stimulated RAW 264.7 cells and DPPH radical scavenging activities.Compared with positive control (L-NMMA), they were potently reduced nitric oxide productions and showed anti-oxidative activities [135].Nine succinic acid derivatives ( 228 -236), eleven quinic acid ( 245 -255) derivatives and two shikimic acid derivatives ( 256 and 257) were isolated from the fruits ofA.arguta.The NF-κB transcriptional inhibitory activity of the compounds was evaluated using RAW 264.7 macrophages cells induced by lipopolysaccharide.Among the groups of diff erent organic acid derivatives, the quinic acid derivatives inhibited NF-κB transcriptional activity with an IC 50 value of 4.0 μM [136].

Fig.8 Structures of flavones, isofl avones, and flavonols 155 -202 from Actinidia plants

Fig.8 (continued)

Fig.8 (continued)

Fig.8 (continued)

Fig.8 (continued)

2.3.7 Coumarins

Coumarins are rarely identifi ed from kiwifruit plants, and only eleven members have been reported ( 258-267, Fig. 11, Table 10).Umbelliferone 258 was obtained from the leaves ofA.polygama(Sieb.et Zucc.) Miq [109].A number of studies demonstrate the pharmacological properties of 258 including antitumor, anti-infl ammatory, antioxidant, antidiabetic, and immunomodulatory activities [143– 149].It showed cytotoxicity against MCF-7 and MDA-MB-231 cell lines with IC 50 values of 15.56 and 10.31 μM, respectively [148].Phytochemical examination of the fruits ofA.argutaled to the isolation of esculetin 259 [135].Two coumarins were isolated from the roots ofA.deliciosaand identifi ed as fraxetin 260 and isoscopoletin 261 [150].Compound 260 showed potent inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) generation with an IC50value of 10.11 ± 0.47 μM [151].Esculin 263 and fraxin 264 were characterized from the stems and fruits ofA.deliciosa(kiwifruit) andA.chinensis[152].Compound 264 showed inhibitory activity towards HepG2 with an IC50value of 14.71 μM [153].

2.3.8 Lignans

Lignans also had a narrow distribution in kiwi plants, only six members have been identified fromActinidiaplants ( 269-274, Fig. 12, Table 11).(+)-Pinoresinol 271, (+)-medioresinol 272, and (?)-syringaresinol 273 were partitioned from the fraction of the roots ofA.arguta[53].Compound 271 is a biologically active lignan and widely found in many dietary plants.It was reported to possess antifungal, anti-infl ammatory, antioxidant, hypoglycemic, and antitumor activities [158– 162].A study on this compound suggested that 271 displayed signifi cant inhibition of fMLP/CB-induced superoxide anion generation and elastase release, with an IC50value of 1.3 ± 0.2 μg/mL [159].The 50% ethanol extract ofA.argutashowed strong inhibitory eff ect onα-glucosidase (32.6%), while a bio-guided isolation on the extract gave a bioactive compound pinoresinol diglucoside 274 [138].

Table 7 Information of flavones, isofl avones, and flavonols from Actinidia plants

Table 7 (continued)

2.3.9 Simple Phenols

Simple benzene derivatives including glycosides and isoprenylated benzene products fromActinidiaplants were collected ( 275 -298, Fig. 13, Table 12).Phytochemical examination of the fruits ofA.argutaled to the isolation of protocatechuic acid 279 [135].It showed anti-infl ammatory [163], antioxidant [163], neuroprotective [164], and antiproliferative activities [165].Protocatechuic acid exhibited signifi cant (p < 0.05) anti-infl ammatory (83% and 88% inhibition for egg-albumin induced and xylene induced oedema, respectively), analgesic (56% inhibition and 22 s of pain suppression for acetic acid-induced and hot plate-induced pain, respectively), and antioxidant eff ects (97% inhibition and absorbance of 2.516 at 100 μg/mL for DPPH and FRAP assay, respectively) in the models [166].Extraction of leaf tissue from the golden-fl eshed kiwifruit cultivarA.chinensis“Hort16A” expressing genotype-resistance against the fungusBotrytis cinerea, a new phenolic compound, 3,5-dihydroxy-2-(methoxycarbonylmethyl)phenyl 3,4-dihydroxybenzoate 278 was therefore obtained [167].

Four novel skeleton phenolic compounds planchols A-D ( 291-294) were isolated from the roots ofA.chinensisPlanch.Their structures were elucidated by spectroscopic analysis and chemical evidence.The structure of 291 was further confi rmed by the single-crystal X-ray diff raction.Moreover, it was found that 291 and 292 showed remarkable cytotoxic activity against P-388 with IC50of 2.50 and 3.85 μM, respectively, and against A-549 with IC50of 1.42 and 2.88 μM, respectively [94].

Fig.9 Structures of xanthones, isofl avones, and flavonols 203 -219 from Actinidia plants

Table 8 Information of xanthones, anthocyanins, and emodins from Actinidia plants

2.4 Miscellaneous

Three alkaloids ( 299 -301), eleven fatty acids and derivatives ( 302 -312), and other thirteen small molecules ( 313 -325) were obtained fromActinidiaplants (Fig. 14, Table 13).Actinidine 299 and boschniakine 300 were isolated from the leaves and galls ofA.polygamaand also isolated fromA.argutawhich might be converted from iridoids [174,175].A bioassay-guided fractionation of the fruits ofA.polygamaled to the separation and identifi cation of a polyunsaturated fatty acid,α-linolenic acid (ALA) 305 [176].This compound was found to possess a broad biological properties including anti-infl ammatory [177], anti-tumor [178], anti-hyperlipidemic [179], anti-diabetic [180], and anti-fungal [181] activities.By a bio-guided fractionation, a ceramide namely actinidiamide 312 was identifi ed as an anti-infl ammatory component from the EtOAc fraction ofA.polygamaMax.It potently inhibited nitric oxide production (30.6% inhibition at 1 μg/mL) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells andβ-hexosaminidase release (91.8% inhibition at 1 μg/mL) in IgE-sentized RBL-2H3 cells [182].

Fig.10 Structures of phenylpropionic acids 220 -257 from Actinidia plants

Table 9 Information of phenylpropionic acids from Actinidia plants

Fig.11 Structures of coumarins 258 -268 from Actinidia plants

Table 10 Information of coumarins from Actinidia plants

Fig.12 Structures of lignans 269-274 from Actinidia plants

Table 11 Information of of lignans from Actinidia plants

Fig.13 Structures of simple phenols 275-298 from Actinidia plants

In summary, this review focused on the biological components and related pharmacological activities of various parts ofActinidiaplants, including triterpenoids, steroids, flavonoids, catechins, coumarins, lignans, phenols, and other small organic molecules.A total of 325 molecules have been collected in this review.Most of the active molecules are derived from the roots ofActinidiaplants, while triterpenes and flavonoids are the most important types regardless of the number of compounds and their biological activity signifi -cance.The stems, leaves, fruit galls, and other parts of kiwi are mainly rich in flavonoids, phenylpropionic acids, and other small molecule compounds.Currently, these chemical components are not structurally novel.In addition, there are few in-depth researches on pharmacological activities of the bioactive compounds.Therefore, research on the chemical constituents ofActinidiaplants is still promising.We hope that this review can provide positive information for the further exploration of the chemical components and their biological activities ofActinidiaplants.

Table 12 Information of simple phenols from Actinidia plants

Fig.14 Structures of other molecules 299-325 from Actinidia plants

Table 13 Information other molecules from Actinidia plants

FundingThis work was fi nancially supported by the National Natural Science Foundation of China (22177139) and the Scientifi c Research Program of Hubei Provincial Department of Education, China (D20183001).

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