Withanolides from Physalis hispida

Natural withanolides, an update

Covering: March 2010 to December 2020. Previous review: Nat. Prod. Rep., 2011, 28, 705This review summarizes the latest progress and perspectives on the structural classification, biological activities and mechanisms, metabolism and pharmacokinetic investigations, biosynthesis, chemical synthesis and structural modifications, as well as future research directions of the promising natural withanolides. The literature from March 2010 to December 2020 is reviewed, and 287 references are cited.

Withanolides from the genus Exodeconus (Solanaceae). Chemotaxonomical considerations

Five Exodeconus species were phytochemically analyzed. From the aerial parts of E. pusillus, the 7α,27-dihydroxy-1-oxo-22R-witha-2,5,24-trienolide and three other previously unreported normal-type withanolides were isolated. All the studied species had normal type and/or ring-D aromatic withanolides, and some had already been isolated from other Solanaceae genera, and therefore, these compounds are not chemotaxonomic markers at the generic level. The chemical composition of an undescribed Exodeconus species analyzed here supports the designation of this taxon as a new entity. The integral chemical profile of Exodeconus can be evaluated for its taxonomic implication when a more robust phylogeny of Solanaceae is available that allows the phylogenetic relationships with its closest genera to be clarified.

Withanolides from the genus Physalis: a review on their phytochemical and pharmacological aspects

Objectives

Withanolides are a group of modified C28 ergostane-type steroids with a C-22, C-26 δ-lactone side chain or a C-23, C-26 γ-lactone side chain. They enjoy a limited distribution in the plant kingdom and predominantly occur in several genera of Solanaceae. Of which, the genus Physalis is an important resource for this type of natural molecules. The present review aims to comprehensively illustrate the structural characteristics and classification of withanolides, and particularly focus on the progression on phytochemical and pharmacological aspects of withanolides from Physalis ranging from January 2015 to June 2019.

Key findings

Approximately 351 natural withanolides with novel and unique structures have so far been identified from genus Physalis, mainly isolated from the species of P. angulata and P. peruviana. Withanolides demonstrated diverse biological activity, such as anticancer, anti-inflammatory, antimicrobial, immunoregulatory, trypanocidal and leishmanicidal activity. Their observed pharmacological functions supported the uses of Physalis species in traditional or folk medicines.

Summary

Due to their unique structure skeleton and potent bioactivities, withanolides are regarded to be promising drug candidates, particularly for developing anticancer and anti-inflammatory agents. Further investigations for discovering novel withanolides of genus Physalis, exploiting their pharmacological values and evaluating their potency as therapeutic agents are significant work.

Three new C23 steroids from the leaves and stems of Nicandra physaloides

Nicandra physaloides is a medicinal and edible plant and has been used as traditionally herbal medicine to treat various diseases in folk. Its characteristic withanolides, a kind of ergostane-type steroids, are reported to display plentiful biological activities that many explain the effect of N. physaloides to some extent. Thus, to further find bioactive steroids, the stems and leaves of N. physaloides were investigated and three new C23 steroids, nic-physatones I-J (1-2), and nic-physatone S (3), together with a known C25 steroid, nic 17 (4), were isolated. Their structures were elucidated by extensive 1D NMR and 2D NMR (HSQC, HMBC, ¹H-¹H COSY, and ROESY), UV and MS analyses. Compounds 1-3 possess a rare C23 steroid skeleton. Among them, compound 3 represented the first example of a C23 steroid featuring a benzene ring (D ring). The isolated compounds showed no cytotoxic activity.

Three new withanolides from the calyces of Nicandra physaloides

Chemical investigation on ethyl acetate extract of the calyces of Nicandra physaloides resulted in the isolation of three new withanolides named as nicphysatone A (1), nicphysatone B (2), nicphysatone C (3), together with five known withanolides, nic 17 (4), nic 7 (5), nic 2 (6), withahisolide G (7) and nicaphysalin B (8). The structures were determined by comprehensive spectroscopic experiments. The discovery enriched the diversity of natural withanolides and could serve as scaffolds for the synthesis of more potent modified withanolides.

Anti-ulcer and anti-Helicobacter pylori potentials of the ethyl acetate fraction of Physalis alkekengi L. var. franchetii (Solanaceae) in rodent

ETHNOPHARMACOLOGICAL RELEVANCE

Physalis alkekengi L. var. franchetii (Solanaceae) has been widely used in Chinese folk medicine due to its wide distribution throughout the country, for the treatment of a wide range of diseases including heat and cold, sore throat, fever, fungal infection, inflammation, toothache, rheumatism, burn, analgesic, ulcer and urinary diseases. However, the effect of P. alkekengi var. franchetii on ulcer and Helicobacter pylori infection has not been reported to date.

AIM OF THE STUDY

This study was designed to investigate the anti-inflammatory, anti-ulcer, anti-Helicobacter pylori and analgesic properties of ethyl acetate fraction of the crude aqueous methanolic extract from the aerial parts of the plant P. alkekengi L. var. franchetii in rodents.

MATERIALS AND METHODS

Acute toxicity of the crude extract of P. alkekengi L. var. franchetii (PAF) was evaluated in rats. The petroleum ether fraction (PEF), butanol fraction (BF), ethyl acetate fraction (EAF) and aqueous fraction (AF) of crude aqueous methanolic extract from PAF were screened for anti-inflammatory and anti-ulcer potential at doses of 100, 250 and 500mg/kg (p.o.), using carrageenin-induced hind paw edema and ethanol-induced gastric lesions test in rats. In vitro anti-Helicobacter pylori activity of EAF was assayed subsequently. In addition, three doses of EAF were evaluated for analgesic activity using hot plate and writhing tests, respectively. Finally, we performed a phytochemical analysis of EAF.

RESULTS

Four fractions of crude extract from PAF significantly reduced the paw volume in carrageenin-induced hind paw edema model at different doses (100, 250 and 500mg/kg, p.o.). The fraction EAF at a dose of 500mg/kg exhibited the highest (75.92%) (0.150 ± 0.045***, ***p < 0.001) anti-inflammatory potential, which is similar to indomethacin (***P < 0.001)（0.120 ± 0.014***, 80.74% inhibition of inflammation） at 5mg/kg. Pretreatment with EAF (500mg/kg, p.o.) significantly reduced the intensity of gastric mucosal damage and showed higher gastroprotective activity (90.6%) when compared to the standard drug famotidine (84.6%). In addition, EAF fraction also showed a moderate (P < 0.05) anti-Helicobacter pylori activity with a minimal inhibition concentration (MIC) of 500μg/ml. Furthermore, pain sensation was effectively inhibited at 500mg/kg, p.o. of EAF as manifested by an increase (p < 0.001) of latency time in hot plate from 30 to 90min and a decrease (p < 0.001) in count of writhing induced by acetic acid. By HPLC, we determined some steroid, terpenoid and flavonoids (four compounds): kaempferol, quercetin, Blumenol A and physalindicanols A, which were isolated from the ethyl acetate fraction and identified using ¹H NMR and ¹³C NMR spectra analysis.

CONCLUSION

This study demonstrated the anti-inflammatory, anti-ulcer, anti-Helicobacter pylori and analgesic properties of EAF of the crude extract from PAF thus justifying its traditional usage.

Phytochemical Study of the Genus Salpichroa (Solanaceae), Chemotaxonomic Considerations, and Biological Evaluation in Prostate and Breast Cancer Cells

Twelve Salpichroa taxa have been phytochemically analyzed. From the aerial parts of S. scandens, four known salpichrolides A, C, I, S, and an unreported withanolide named salpichrolide V (1), were isolated. In S. dependens, S. gayi, S. glandulosa subsp. glandulosa, S. glandulosa subps. weddellii, S. leucantha, S. micrantha, S. microloba, S. proboscidea, S. ramosissima, S. tristis var. tristis, and S. weberbauerii, no withanolides were found. The chemical content of ca. 85% of the Salpichroa taxa is in agreement with molecular studies, which suggest that Salpichroa and Jaborosa, a genus considered morphologically close to Salpichroa, are distant in the systematic of the Solanoideae subfamily. Moreover, the in vitro cytotoxic activity of a set of natural salpichrolides and derivatives was examined against two prostate carcinoma cell lines (PC3 and LNCaP) and two human breast cancer cell lines (MCF-7 and T47D). Several compounds showed moderate activity (IC₅₀  = 64.91 - 29.97 μm).

Withanolides from aerial parts of Nicandra physalodes

Twenty withanolides, including previously unknown nicanlodes A-M, were isolated from aerial parts of Nicandra physalodes. Their structural elucidations were unambiguously achieved through interpretation of extensive spectroscopic data (NMR and HRMS) and by comparison with literature data. Nicanlodes A and B have an unusual aromatic amine moiety. The isolated compounds were evaluated for their cytotoxicity against five human cancer cell lines.

Withanolides from the stems and leaves of Physalis pubescens and their cytotoxic activity

A phytochemical study of Physalis pubescens L. afforded twelve compounds, including six new withanolides (1, 4, and 6i-9), four new withanolide glucosides (2, 3, 5, and 6), and two known withanolides (10 and 11). Their structures were established via extensive spectroscopic analysis. The absolute configuration of 3 was assigned using X-ray crystallography, and the absolute configurations of the 1,2-diol moiety in 1 were determined using the in situ dimolybdenum electronic circular dichroism method. Compounds 7, 9, and 10 exhibited significant cytotoxicity against human prostate cancer cells (C4-2B and 22Rvl), human renal carcinoma cells (786-O, A-498, Caki-2, and ACHN), human melanoma cells (A375 and A375-S2), and human normal hepatic cell line (L02) with IC₅₀ values in the range of 0.17-5.30μM.

17β-Hydroxy-18-acetoxywithanolides from Aeroponically Grown Physalis crassifolia and Their Potent and Selective Cytotoxicity for Prostate Cancer Cells

When cultivated under aeroponic growth conditions, Physalis crassifolia produced 11 new withanolides (1-11) and seven known withanolides (12-18) including those obtained from the wild-crafted plant. The structures of the new withanolides were elucidated by the application of spectroscopic techniques, and the known withanolides were identified by comparison of their spectroscopic data with those reported. Withanolides 1-11 and 16 were evaluated for their potential anticancer activity using five tumor cell lines. Of these, the 17β-hydroxy-18-acetoxywithanolides 1, 2, 6, 7, and 16 showed potent antiproliferative activity, with some having selectivity for prostate adenocarcinoma (LNCaP and PC-3M) compared to the breast adenocarcinoma (MCF-7), non-small-cell lung cancer (NCI-H460), and CNS glioma (SF-268) cell lines used. The cytotoxicity data obtained for 12-15, 17, and 19 have provided additional structure-activity relationship information for the 17β-hydroxy-18-acetoxywithanolides.

Withanolide Structural Revisions by (13)C NMR Spectroscopic Analysis Inclusive of the γ-Gauche Effect

A classic withanolide is defined as a highly oxygenated C28 ergostane-type steroid that is characterized by a C22-hydroxy-C26-oic acid δ-lactone in the nine-carbon side chain. Analysis of the reported (13)C NMR data of classic withanolides with hydroxy groups (C-14, C-17, and C-20) revealed that (1) a hydroxy (C-14 or C-17) substituent significantly alters the chemical shifts (C-7, C-9, C-12, and C-21) via the γ-gauche effect; (2) the chemical shift values (C-9, C-12, and C-21) reflect the orientation (α or β) of the hydroxy moiety (C-14 or C-17); (3) a double-bond positional change in ring A (Δ(2) to Δ(3)), or hydroxylation (C-27), results in a minuscule effect on the chemical shifts of carbons in rings C and D (from C-12 to C-18); and (4) the (13)C NMR γ-gauche effect method is more convenient and reliable than the traditional approach ((1)H NMR shift comparisons in C5D5N versus CDCl3) to probe the orientation of the hydroxy substituent (C-14 and C-17). Utilization of these rules demonstrated that the reported (13)C NMR data of withanolides 1a-29a were inconsistent with their published structures, which were subsequently revised as 1-16 and 12 and 18-29, respectively. When combined, this strongly supports the application of these methods to determine the relative configuration of steroidal substituents.

Withanolides and Sucrose Esters from Physalis neomexicana

Four withanolides (1-4) and two sucrose esters (5, 6) were isolated from the aerial parts of Physalis neomexicana. The structures of 1-6 were elucidated through a variety of spectroscopic techniques. Cytotoxicity studies of the isolates revealed that 2 inhibited human breast cancer cell lines (MDA-MB-231 and MCF-7) with IC50 values of 1.7 and 6.3 μM, respectively.

Withanolides from Physalis coztomatl

Six withanolides (1-6), as well as two known withanolides (physachenolide D 7 and withanoside VI 8), were isolated from the aerial parts of Physalis coztomatl (Solanaceae). Structural elucidations of 1-6 were achieved through 2D NMR and other spectroscopic techniques, while the structure of 1 was confirmed by X-ray crystallographic analysis. In addition, the stereochemical orientation of the 17-hydroxy group in withanolides was discussed in relation to (13)C NMR shifts of C-12, 13, 14 and 16. Such analysis established that coagulansin A contains a 17α-hydroxy moiety rather than the reported 17β-hydroxy functionality, and has been revised accordingly.

Capsisteroids A–F, withanolides from the leaves of Solanum capsicoides

A known withanolide steroid cilistol G (1) and six new withanolides, capsisteroids A–F (2–7), were isolated from the EtOAc extract of the leaves of Solanum capsicoides.

Antiproliferative withanolides from several solanaceous species

To date, our work on solanaceous species (Datura wrightii, Jaborosa caulescens, Physalis hispida, Physalis longifolia, Vassobia breviflora and Withania somnifera) has resulted in the isolation of 65 withanolides, 31 of which were new, as well as the semi-synthesis of a further 30 withanolides. Structure identification and MTS assay-based antiproliferative evaluation of these 95 compounds revealed that a Δ(2)-1-oxo functionality in ring A, in conjunction with either a 5β,6β-epoxy or 5α-chloro-6β-hydroxy moiety in ring B, is the minimum structural requirement for withanolides to produce potent cytotoxic activity. Such structure-activity relationship analysis also revealed that oxygenation (the -OH or -OR groups) at C-4, 7, 11 and 12, as well as C-14 to C-28, did not contribute towards the observed antiproliferative activity. Herein, we present a complete overview of our work as it relates to the withanolides reported from 1965 to 2013.