Antimycobacterial physalins from Physalis angulata L. (Solanaceae)

Physalin H, physalin B, and isophysalin B suppress the quorum-sensing function of Staphylococcus aureus by binding to AgrA

The virulence of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), depends on the expression of toxins and virulence factors controlled by the quorum-sensing (QS) system, encoded on the virulence accessory gene regulator (agr) locus. The aim of this study was to identify a phytochemical that inhibits Agr-QS function and to elucidate its mechanism. We screened 577 compounds and identified physalin H, physalin B, and isophysalin B--phytochemicals belonging to physalins found in plants of the Solanaceae family--as novel Agr-QS modulators. Biological analyses and in vitro protein-DNA binding assays suggested that these physalins suppress gene expression related to the Agr-QS system by inhibiting binding of the key response regulator AgrA to the agr promoters, reducing the function of hemolytic toxins downstream of these genes in MRSA. Furthermore, although physalin F suppressed gene expression in the Agr-QS system, its anti-hemolytic activity was lower than that of physalins H, B, and isophysalin B. Conversely, five physalins isolated from the same plant with the ability to suppress Agr-QS did not reduce bacterial Agr-QS activity but inhibited AgrA binding to DNA in vitro. A docking simulation revealed that physalin interacts with the DNA-binding site of AgrA in three docking states. The carbonyl oxygens at C-1 and C-18 of physalins, which can suppress Agr-QS, were directed to residues N201 and R198 of AgrA, respectively, whereas these carbonyl oxygens of physalins, without Agr-QS suppression activity, were oriented in different directions. Next, 100-ns molecular dynamics simulations revealed that the hydrogen bond formed between the carbonyl oxygen at C-15 of physalins and L186 of AgrA functions as an anchor, sustaining the interaction between the carbonyl oxygen at C-1 of physalins and N201 of AgrA. Thus, these results suggest that physalin H, physalin B, and isophysalin B inhibit the interaction of AgrA with the agr promoters by binding to the DNA-binding site of AgrA, suppressing the Agr-QS function of S. aureus. Physalins that suppress the Agr-QS function are proposed as potential lead compounds in the anti-virulence strategy for MRSA infections.

UPLC-Q-Orbitrap-MS/MS-Guided Isolation of Bioactive Withanolides from the Fruits of Physalis angulata

Physalis angulata Linn. is an exotic Amazonian fruit that is commonly recognized as wild tomato, winter cherry, and gooseberry. While its fruit is known to contain many nutrients, such as minerals, fibers, and vitamins, few papers have investigated withanolide derivatives from its fruits. UPLC-Q-Orbitrap-MS/MS, which produces fragmentation spectra, was applied for the first time to guide the isolation of bioactive withanolide derivatives from P. angulata fruits. As a result, twenty-six withanolide derivatives, including two novel 1,10-secowithanolides (1 and 2) and a new derivative (3), were obtained. Compounds 1 and 2 are rare rearranged 1,10-secowithanolides with a tetracyclic 7/6/6/5 ring system. All structures were assigned through various spectroscopic data and quantum chemical calculations. Nine withanolide derivatives exhibited significant inhibitory effects on three tumor cell lines with IC50 values of 0.51-13.79 μM. Moreover, three new compounds (1-3) exhibited potential nitric oxide inhibitory effects in lipopolysaccharide-stimulated RAW264.7 cells (IC50: 7.51-61.8 μM). This investigation indicated that fruits of P. angulata could be applied to treat and prevent cancer and inflammatory-related diseases due to their potent active withanolide derivatives.

On the Efficiency of the Density Functional Theory (DFT)-Based Computational Protocol for 1H and 13C Nuclear Magnetic Resonance (NMR) Chemical Shifts of Natural Products: Studying the Accuracy of the pecS-n (n = 1, 2) Basis Sets

The basis set issue has always been one of the most important factors of accuracy in the quantum chemical calculations of NMR chemical shifts. In a previous paper, we developed new pecS-n (n = 1, 2) basis sets purposed for the calculations of the NMR chemical shifts of the nuclei of the most popular NMR-active isotopes of 1-2 row elements and successfully approbated these on the DFT calculations of chemical shifts in a limited series of small molecules. In this paper, we demonstrate the performance of the pecS-n (n = 1, 2) basis sets on the calculations of as much as 713 1H and 767 13C chemical shifts of 23 biologically active natural products with complicated stereochemical structures, carried out using the GIAO-DFT(PBE0) approach. We also proposed new alternative contraction schemes for our basis sets characterized by less contraction depth of the p-shell. New contraction coefficients have been optimized with the property-energy consistent (PEC) method. The accuracies of the pecS-n (n = 1, 2) basis sets of both the original and newly contracted forms were assessed on massive benchmark calculations of proton and carbon chemical shifts of a vast variety of natural products. It was found that less contracted pecS-n (n = 1, 2) basis sets provide no noticeable improvement in accuracy. These calculations represent the most austere test of our basis sets as applied to routine calculations of the NMR chemical shifts of real-life compounds.

Antibacterial and Antifungal Terpenes from the Medicinal Angiosperms of Asia and the Pacific: Haystacks and Gold Needles

This review identifies terpenes isolated from the medicinal Angiosperms of Asia and the Pacific with antibacterial and/or antifungal activities and analyses their distribution, molecular mass, solubility, and modes of action. All data in this review were compiled from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and library searches from 1968 to 2022. About 300 antibacterial and/or antifungal terpenes were identified during this period. Terpenes with a MIC ≤ 2 µg/mL are mostly amphiphilic and active against Gram-positive bacteria, with a molecular mass ranging from about 150 to 550 g/mol, and a polar surface area around 20 Ų. Carvacrol, celastrol, cuminol, dysoxyhainic acid I, ent-1β,14β-diacetoxy-7α-hydroxykaur-16-en-15-one, ergosterol-5,8-endoperoxide, geranylgeraniol, gossypol, 16α-hydroxy-cleroda-3,13 (14)Z-diene-15,16-olide, 7-hydroxycadalene, 17-hydroxyjolkinolide B, (20R)-3β-hydroxy-24,25,26,27-tetranor-5α cycloartan-23,21-olide, mansonone F, (+)-6,6'-methoxygossypol, polygodial, pristimerin, terpinen-4-ol, and α-terpineol are chemical frameworks that could be candidates for the further development of lead antibacterial or antifungal drugs.

A new 1,2-diketone physalin isolated from Physalis minima and TRAIL-resistance overcoming activity of physalins

A new 1,2-diketone physalin, physalin XII (1), and 13 known compounds were isolated from the methanol extract of Physalis minima whole plant collected in Thailand. Among them, five physalins (2-6) had tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistance overcoming activity, and physalin F (3) was the most active with an IC50 value of 0.39 µM against human gastric adenocarcinoma cell line AGS in the presence of TRAIL (100 ng/mL). An investigation of the TRAIL-resistance overcoming activity of physalins using western blot analysis showed that 3 promoted TRAIL-induced apoptosis by suppressing anti-apoptotic proteins c-FLIP and Bcl-2.

Anti-leishmanial physalins-Phytochemical investigation, in vitro evaluation against clinical and MIL-resistant L. tropica strains and in silico studies

Cutaneous leishmaniasis (CL) is a major health problem in over 98 countries of the world, including Pakistan. The current treatments are associated with a number of adverse effects and availability problem of drugs. Therefore, there is an urgent need of easily available and cost effective treatments of CL- in Pakistan. The bioassay-guided fractionation and purification of crude extract of Physalis minima has led to the isolation of a new aminophysalin B (1), and eight known physalins, physalin B (2), 5ß,6ß-epoxyphysalin B (3), 5α-ethoxy-6ß-hydroxy-5,6-dihydrophysalin B (4), physalin H (5), 5ß,6ß-epoxyphysalin C (6), and physalin G (7), K (8), and D (9). It is worth noting that compound 1 is the second member of aminophysalin series, whereas compound 6 was fully characterized for the first time. The structures of compounds 1-9 were elucidated by spectroscopic techniques Whereas, the structural assignments of compounds 1 and 8 were also supported by single-crystal X-ray diffraction studies. The anti-leishmanial activity of isolated physlains 1-9 was evaluated against Leishmania major and Leishmania tropica promastigotes. Compounds 2, 3, and 5-7 (IC50 = 9.59 ± 0.27-23.76 ± 1.10 μM) showed several-fold more potent activity against L. tropca than tested drug miltefosine (IC50 = 42.75 ± 1.03 μm) and pentamidine (IC50 = 27.20 ± 0.01 μM). Whereas compounds 2, 3 and 5 (IC50 = 3.04 ± 1.12-3.76 ± 0.85 μM) were found to be potent anti-leishmanial agents against L. major, several fold more active than tested standard miltefosine (IC50 = 25.55 ± 1.03 μM) and pentamidine (IC50 = 27.20 ± 0.015 μM). Compounds 4 (IC50 = 74.65 ± 0.81 μM) and 7 (IC50 = 39.44 ± 0.65 μM) also showed potent anti-leishmanial ativity against the miltefosine-unresponsive L. tropica strain (MIL resistant) (miltefosine IC50 = 169.55 ± 0.78 μM). Molecular docking and predictive binding studies indicated that these inhibitors may act via targeting important enzymes of various metabolic pathways of the parasites.

New QuEChERS method for quantification of Physalin B and D in Physalis angulata L. in Vietnam

In Vietnam, Physalis angulata L. has been widely used as a traditional medicine to treat fever, anti-inflammatory, and expectorant. Currently, there have been studies on the content of chemical composition especially physalin with anti-diabetic, anti-inflammatory, antibacterial, prevent cancer. This study developed a reliable and sensitive method to determine and validate simultaneous Physalin B and Physalin D in Physalis angulata L.. The QuEChERS method was used for sample preparation from leaf matrices and quantified by using High-performance liquid chromatography coupled with a diode-array detector. The method of research was validated under AOAC and ICH guidance. Chromatography conditions include Agilent C18 column (250mm × 4,6mm; 5µm) with a gradient mode using acetonitrile – methanol-water as mobile phase. The recovery of the method ranged from 94.21 – 105.93% and RSD was from 1.20 – 2.31%, the LOD, and LOQ were 0.4 mg/kg – 2.4 mg/kg, respectively. The results of the study showed that the proposed the new QuEChERS method for quantification of Physalin B and D in Physalis angulata L. in Vietnam.

Silencing Tautomerization to Isolate Unstable Physalins from Physalis minima

The inherent structural instability of some physalins has hampered the isolation and identification of these compounds for approximately 50 years, and an effective method to overcome these challenges remains unavailable. In the present study, the unprecedented tautomerization mechanism of unstable physalins was elucidated by performing isotopic labeling experiments and DFT calculations, which led to the successful separation of tautomers and isolation of highly pure products for the first time. As a result, 15 new physalins, physaminins A-O (1-15), as well as 17 known analogues (16-32), were isolated from the whole plants of Physalis minima L. The chemical structures of the new compounds were established by performing a comprehensive analysis of spectroscopic data, and their absolute configurations were confirmed by using computational ECD calculations and/or single-crystal X-ray diffraction analyses. All obtained isolates were evaluated for their antiproliferative effects against four human cancer cell lines (A549, HepG2, MCF-7, and SCG-7901) and two noncancerous cell lines (RAW 264.7 and human normal hepatocytes L02), as well as their anti-inflammatory activities by measuring their abilities to inhibit NO production in LPS-stimulated murine RAW 264.7 cells in vitro. Compounds 1-5, 13, 16, 18, 19, 23, and 30 exerted significant antiproliferative effects on the four human cancer lines, with IC₅₀ values ranging from 0.2(0) to 24.7(2) μM, and these compounds were not toxic to the two noncancerous cell lines at a concentration of 10 μM. Moreover, compounds 7, 10, 11, 12, 14, 17, 22, and 27 significantly inhibited NO production, with IC₅₀ values ranging from 2.9(1) to 9.5(2) μM.

Combined Computational NMR and Molecular Docking Scrutiny of Potential Natural SARS-CoV-2 Mpro Inhibitors

In continuation of the search for potential drugs that inhibit the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in this work, a combined approach based on the modeling of NMR chemical shifts and molecular docking is suggested to identify the possible suppressors of the main protease of this virus among a number of natural products of diverse nature. Primarily, with the aid of an artificial neural network, the problem of the reliable determination of the stereochemical structure of a number of studied compounds was solved. Complementary to the main goal of this study, theoretical modeling of NMR spectral parameters made it feasible to perform a number of signal reassignments together with introducing some missing NMR data. Finally, molecular docking formalism was applied to the analysis of several natural products that could be chosen as prospective candidates for the role of potential inhibitors of the main protease. The results of this study are believed to assist in further research aimed at the development of specific drugs based on the natural products against COVID-19.

Natural Products from Physalis alkekengi L. var. franchetii (Mast.) Makino: A Review on Their Structural Analysis, Quality Control, Pharmacology, and Pharmacokinetics

The calyxes and fruits of Physalis alkekengi L. var. franchetii (Mast.) Makino (P. alkekengi), a medicinal and edible plant, are frequently used as heat-clearing and detoxifying agents in thousands of Chinese medicine prescriptions. For thousands of years in China, they have been widely used in clinical practice to treat throat disease, hepatitis, and bacillary dysentery. This systematic review summarizes their structural analysis, quality control, pharmacology, and pharmacokinetics. Furthermore, the possible development trends and perspectives for future research studies on this medicinal plant are discussed. Relevant information on the calyxes and fruits of P. alkekengi was collected from electronic databases, Chinese herbal classics, and Chinese Pharmacopoeia. Moreover, information was collected from ancient documents in China. The components isolated and identified in P. alkekengi include steroids, flavonoids, phenylpropanoids, alkaloids, nucleosides, terpenoids, megastigmane, aliphatic derivatives, organic acids, coumarins, and sucrose esters. Steroids, particularly physalins and flavonoids, are the major characteristic and bioactive ingredients in P. alkekengi. According to the literature, physalins are synthesized by the mevalonate and 2-C-methyl-d-erythritol-4-phosphate pathways, and flavonoids are synthesized by the phenylpropanoid pathway. Since the chemical components and pharmacological effects of P. alkekengi are complex and varied, there are different standards for the evaluation of its quality and efficacy. In most cases, the analysis was performed using high-performance liquid chromatography coupled with ultraviolet detection. A pharmacological study showed that the crude extracts and isolated compounds from P. alkekengi had extensive in vitro and in vivo biological activities (e.g., anti-inflammatory, anti-tumor, immunosuppressive, antibacterial, anti-leishmanial, anti-asthmatic, anti-diabetic, anti-oxidative, anti-malarial, anti-Alzheimer's disease, and vasodilatory). Moreover, the relevant anti-inflammatory and anti-tumor mechanisms were elucidated. The reported activities indicate the great pharmacological potential of P. alkekengi. Similarly, studies on the pharmacokinetics of specific compounds will also contribute to the progress of clinical research in this setting.

Simple and Versatile Scheme for the Stereochemical Identification of Natural Products and Diverse Organic Compounds with Multiple Asymmetric Centers

A simple and versatile scheme of stereochemical identification of the stereochemically rich natural products and organic compounds with multiple asymmetric centers is proposed based on a detailed parsing of calculated ¹H and ¹³C NMR chemical shifts in combination with their DP4+ analysis, as exemplified for three natural products: sungucine, physalin D, and anabsinthin. Performed benchmark calculations of the considered diastereomers provided very good agreement with their known experimental stereochemical structures.

Naturally occurring physalins from the genus Physalis: A review

Physalins, including physalins and neophysalins, are a class of highly oxygenated ergostane-type steroids. They are commonly known by the name of 16,24-cyclo-13,14-seco steroids, in which the disconnection of C-13 and C-14 produces an eight or nine-membered ring and the carbocyclization of C-16 and C-24 generates a new six-membered ring. Meanwhile, the oxidation of C-18 methyl to carboxyl group forms a 18,20-lactone, and the oxidation of C-14 and C-17 gets a heterocyclic oxygen acrossing rings C and D. Additionly, physalins frequently form an oxygen bridge to connect C-14 to C-27. Physalins are a kind of characteristic constituents from the species of the genus Physalis (Solanaceae), which are reported with a wide array of pharmacological activities, including anticancer, anti-inflammatory, immunoregulatory, antimicrobial, trypanocidal and leishmanicidal, antinociceptive, antidiabetic and some other activities. Herein,the research progress of physalins from the genus Physalis during the decade from 1970 to 2021 on phytochemistry, pharmacology, pharmacokinetics and application in China are systematically presented and discussed for the first time.

Traditional Medicinal Plants as a Source of Antituberculosis Drugs: A System Review

Medicinal plants are the chief components in the different oriental formulations in different traditional medical systems worldwide. As a thriving source of medicine, the medicinal plants with antituberculosis (TB) properties inspire the pharmacists to develop new drugs based on their active components or semimetabolites. In the present review, the anti-TB medicinal plants were screened from the scientific literatures, based on the botanical classification and the anti-TB activity. The obtained anti-TB medicinal plants were categorized into three different categories, viz., 159 plants critically examined with a total 335 isolated compounds, 131 plants with their crude extracts showing anti-TB activity, and 27 plants in literature with the prescribed formula by the traditional healers. Our systemic analysis on the medicinal plants can assist the discovery of novel and more efficacious anti-TB drugs.

Physalin pool from Physalis angulata L. leaves and physalin D inhibit P2X7 receptor function in vitro and acute lung injury in vivo

P2X7 receptor promotes inflammatory response and neuropathic pain. New drugs capable of impairing inflammation and pain-reducing adverse effects extracted from plant extracts have been studied. Physalis angulate L. possesses traditional uses and exhibits antiparasitic, anti-inflammatory, antimicrobial, antinociceptive, antimalarial, antileishmanial, immunosuppressive, antiasthmatic. diuretic, and antitumor activities. The most representative phytochemical constituents identified with medicinal importance are the physalins and withanolides. However, the mechanism of anti-inflammatory action is scarce. Although some physalins and withanolides subtypes have anti-inflammatory activity, only four physalins subtypes (B, D, F, and G) have further studies. Therefore, we evaluated the crude ethanolic extract enriched with physalins B, D, F, and G from P. angulata leaves, a pool containing the physalins B, D, F, G, and the physalins individually, as P2X7 receptor antagonists. For this purpose, we evaluated ATP-induced dye uptake, macroscopic currents, and interleukin 1-β (IL-1β) in vitro. The crude extract and pool dose-dependently inhibited P2X7 receptor function. Thus, physalin B, D, F, and G individually evaluated for 5'-triphosphate (ATP)-induced dye uptake assay, whole-cell patch-clamp, and cytokine release showed distinct antagonist levels. Physalin D displayed higher potency and efficacy than physalin B, F, and G for all these parameters. In vivo mice model as ATP-induced paw edema was potently inhibited for physalin D, in contrast to physalin B, F, and G. ATP and lipopolysaccharide (LPS)-induced pleurisy in mice were reversed for physalin D treatment. Molecular modeling and computational simulation predicted the intermolecular interactions between the P2X7 receptor and physalin derivatives. In silico results indicated physalin D and F as a potent allosteric P2X7 receptor antagonist. These data confirm physalin D as a promisor source for developing a new P2X7 receptor antagonist with anti-inflammatory action.

Two new physalins from Physalis alkekengi L. var. franchetii (Mast.) Makino

Two new physalins, 7α-hydroxy-5-deoxy-4-dehydrophysalin IX (1) and 5-deoxy-4-dehydrophysalin IX (2), together with six known compounds, luteolin (3), luteolin-7-O-glucoside (4), neoechinulin A (5), 3-(4-hydroxy-3-methoxyphenyl)-N-(4-methylphenyl)-2-propenamide (6), physalin D (7) and blumenol A (8) were isolated from Physalis alkekengi L. var. franchetii (Mast.) Makino. Their structures were elucidated by NMR spectroscopic analysis, HR-ESI-MS, X-ray crystallographic data analysis and comparison with the known compounds. Among them, compounds 5 and 6 were isolated from the genus Physalis for the first time. Compound 1 exhibited weak NAD(P)H: quinone reductase (QR) inducing activity.

Endophytic fungi inhabiting Physalis angulata L. plant: diversity, antioxidant, and antibacterial activities of their ethyl acetate extracts

OBJECTIVES

Endophytic fungi are an essential source of biologically active compounds. They have the ability to synthesize secondary metabolites which are the same or have a high degree of similarity to their host plants. In this study, we aimed to explore the biodiversity and the bioactivities of active metabolites produced by 14 endophytic fungi isolated from the medicinal plant Physalis angulata L. (PA).

METHODS

Fourteen endophytic fungi were isolated from the flowers, stems, leaves, and fruit husks of PA. The endophytic fungi were cultured and incubated in the PDB medium at room temperature. After three weeks, the cultures were extracted using ethyl acetate and dried using a rotary evaporator. The antioxidant activity was evaluated against DPPH while antibacterial activity was evaluated against Escherichia coli and Staphylococcus aureus using microdilution technique. TLC analysis was also done to profile the active compounds within the extract.

RESULTS

Hyphomycetes fungus isolated from the flower of PA exhibited a moderate antioxidant activity with an antioxidant index value of 0.59 (IC₅₀ = 52.43 μg/mL). Six isolates have strong antibacterial activity against E. coli and S. aureus with minimum inhibitory concentration (MIC) value ranging from 8-64 μg/mL. These endophytic fungi are one Hyphomycetes fungus isolated from the flower, one Fusarium sp. isolated from the stem, and four Colletotrichum sp. isolated from leaf and fruit husk of PA.

CONCLUSIONS

Endophytic fungi isolated from PA are potential novel sources of active metabolites especially for antibacterial compounds.

HPLC-HRMS Global Metabolomics Approach for the Diagnosis of "Olive Quick Decline Syndrome" Markers in Olive Trees Leaves

Olive quick decline syndrome (OQDS) is a multifactorial disease affecting olive plants. The onset of this economically devastating disease has been associated with a Gram-negative plant pathogen called Xylella fastidiosa (Xf). Liquid chromatography separation coupled to high-resolution mass spectrometry detection is one the most widely applied technologies in metabolomics, as it provides a blend of rapid, sensitive, and selective qualitative and quantitative analyses with the ability to identify metabolites. The purpose of this work is the development of a global metabolomics mass spectrometry assay able to identify OQDS molecular markers that could discriminate between healthy (HP) and infected (OP) olive tree leaves. Results obtained via multivariate analysis through an HPLC-ESI HRMS platform (LTQ-Orbitrap from Thermo Scientific) show a clear separation between HP and OP samples. Among the differentially expressed metabolites, 18 different organic compounds highly expressed in the OP group were annotated; results obtained by this metabolomic approach could be used as a fast and reliable method for the biochemical characterization of OQDS and to develop targeted MS approaches for OQDS detection by foliage analysis.

Natural sucrose esters: Perspectives on the chemical and physiological use of an under investigated chemical class of compounds

The present review describes the chemistry and physiological properties of the sucrose esters (SEs) obtained from natural or synthetic pathways, with emphasis on those that have aliphatic and phenylpropanoid substituents on their sucrose moiety. Synthesis, extraction and characterization methods for the SEs and NSEs are discussed in terms of synthetic procedures, separation techniques and spectroscopic methods. The physiological properties are discussed taking into account the nature of the substituent groups and their regiochemistry (position and number of substitutions) on the sucrose moiety.

A review of nutritional properties and health benefits of Physalis species

The Physalis genus of the Solanaceae family is home to many edible food crops including tomatillo, goldenberry, and groundcherry. These Physalis members have garnered more attention as consumer interest in novel fruits and vegetables has increased because of increasing awareness of the health benefits of eating a diverse diet. As a result of this interest, several preliminary studies were conducted of these Physalis to evaluate their nutritional and chemical profiles associated with health benefits. Results showed these crops contain many essential minerals and vitamins, notably potassium and immune system supporting Vitamin C, also known for its antioxidant activity. Beyond nutritional properties, these crops also contain a class of steroidal lactones called withanolides, which have been recognized for their antitumor, and antinflammatory properties. In some studies, withanolide extract from Physalis species have exhibited cytotoxicity towards cancers cells. Overall, this review focuses on the nutritional and physiochemical properties of tomatillo, goldenberry, and groundcherry and how they relate to human health.

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.

Reversal of Peripheral Neuropathic Pain by the Small-Molecule Natural Product Physalin F via Block of CaV2.3 (R-Type) and CaV2.2 (N-Type) Voltage-Gated Calcium Channels

No universally efficacious therapy exists for chronic pain, a disease affecting one-fifth of the global population. An overreliance on the prescription of opioids for chronic pain despite their poor ability to improve function has led to a national opioid crisis. In 2018, the NIH launched a Helping to End Addiction Long-term plan to spur discovery and validation of novel targets and mechanisms to develop alternative nonaddictive treatment options. Phytochemicals with medicinal properties have long been used for various treatments worldwide. The natural product physalin F, isolated from the Physalis acutifolia (family: Solanaceae) herb, demonstrated antinociceptive effects in models of inflammatory pain, consistent with earlier reports of its anti-inflammatory and immunomodulatory activities. However, the target of action of physalin F remained unknown. Here, using whole-cell and slice electrophysiology, competition binding assays, and experimental models of neuropathic pain, we uncovered a molecular target for physalin F's antinociceptive actions. We found that physalin F (i) blocks CaV2.3 (R-type) and CaV2.2 (N-type) voltage-gated calcium channels in dorsal root ganglion (DRG) neurons, (ii) does not affect CaV3 (T-type) voltage-gated calcium channels or voltage-gated sodium or potassium channels, (iii) does not bind G-protein coupled opioid receptors, (iv) inhibits the frequency of spontaneous excitatory postsynaptic currents (EPSCs) in spinal cord slices, and (v) reverses tactile hypersensitivity in models of paclitaxel-induced peripheral neuropathy and spinal nerve ligation. Identifying CaV2.2 as a molecular target of physalin F may spur its use as a tool for mechanistic studies and position it as a structural template for future synthetic compounds.

Transcriptome-wide identification of microRNAs and functional insights inferred from microRNA-target pairs in Physalis angulata L

Physalis angulata L., a member of the family Solanaceae, is widely used as the folk medicine in various countries. Continuous research efforts are devoted to the discovery of the effective medicinal ingredients from Physalis angulata. However, due to the limited resources of genome and transcriptome sequencing data, only a few studies have been performed at the gene regulatory level. In this study, the transcriptomes of five organs (roots, stems, leaves, flowers and fruits) of Physalis angulata were reported. Based on the transcriptome assembly containing 196,117 unique transcripts, a total of 17,556 SSRs (simple sequence repeats) were identified, which could be useful RNA-based barcoding for discrimination of the plants closely relative to Physalis angulata. Additionally, 24 transcripts were discovered to be the potential microRNA (miRNA) precursors which encode a total of 31 distinct mature miRNAs. Some of these precursors showed organ-specific expression patterns. Target prediction revealed 116 miRNA-target pairs, involving 31 miRNAs and 83 target transcripts in Physalis angulata. Taken together, our results could serve as the data resource for in-depth studies on the molecular regulatory mechanisms related to the production of medicinal ingredients in Physalis angulata.

Cytotoxic Withanolides from the Whole Herb of Physalis angulata L

Physalis angulata L. is a medicinal plant of the Solanaceae family, which is used to produce a variety of steroids. The present study reports on the cytotoxic withanolides of this plant. The species of Physalis angulata L. was identified by DNA barcoding techniques. Two new withanolides (1–2), together with six known analogues (3–8), were isolated from the whole plant of Physalis angulata L. The structures of these new compounds were determined on the basis of extensive spectroscopic data analyses and electronic circular dichroism (ECD) calculations. The withanolides exhibited strong cytotoxic activities against A549, Hela and p388 cell lines. Furthermore, compounds 1 and 2 induced typical apoptotic cell death in A549 cell line according to the evaluation of the apoptosis-inducing activity by flow cytometric analysis.

Effects of estrogen-like plant compounds on the vaginal epithelium pituitary, adrenal glands, and uterus of rats

Plant species with recognized estrogenic activity and widely used by Brazil’s female population to prevent the unpleasant symptoms of menopause were investigated in this work to demonstrate if constituents of taro-inhame (Colocasia esculenta ), cumaru (Dipteryx odorata ), and camapu (Physalis angulata ) have the ability to mimic or interfere with the action of estrogens. Moreover, their potential use as natural sources of estrogen-like substances for hormone replacement therapy was evaluated. (a) In vivo pharmacological assays were conducted to determine the estrogenic effects of D. odorata isoflavone-rich extract, P. angulata physalin-rich extract, and C. esculenta flavonoid glycoside-rich fraction (FG) on endocrine glands and reproductive organs of female rats at three different stages of the life cycle. The protocols consisted of uterotrophic assays and cytological evaluation of vaginal smears to detect mucosa cell alterations correlated with changes in hormone levels in each phase of the estrous cycle of female rats. The results indicated that C. esculenta FG exhibited estrogenic activity in prepubescent, pubescent, and adult ovariectomized female rats, while D. odorata isoflavones only promoted a weight increase in the pituitary gland of prepubescent rats after prolonged treatment and P. angulata physalins induced a weight increment in the adrenal glands of ovariectomized rats. Additionally, C. esculenta exerted a significant effect on the opening of the vaginal canal in prepubescent rats and on vaginal epithelium. Prolonged treatment of ovariectomized rats with FG altered the proportion of different types of vaginal epithelial cells in these animals, suggesting an interference of FG with estrogen levels. Colocasia esculenta FG induced hypertrophy of the uterus and pituitary in ovariectomized rats similar to estradiol. To elucidate the mechanism of action of FG, its effects were compared to those of estradiol and of the selective estrogen receptor modulator raloxifene. The results suggest that the efficacy of C. esculenta FG is mediated by binding to selective estrogen receptors present in each organ and that raloxifene inhibits the mechanism of action of FG in the same way as it inhibits the effects of estradiol. The overall findings indicate that C. esculenta FG mimics the action of estrogens, with reduced harmful effects on specific tissues.

Physalin B Suppresses Inflammatory Response to Lipopolysaccharide in RAW264.7 Cells by Inhibiting NF-κB Signaling

Physalin B from Physalis angulata L. (Solanaceae) is a naturally occurring secosteroid with multiple biological activities. But its anti-inflammatory activity and mechanism remain unclear. Physalin B effects on RAW264.7 macrophages stimulated by lipopolysaccharide (LPS) were observed in this study. The expression and secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) induced by LPS were significantly inhibited by physalin B. Meanwhile, the NF-κB nuclear translocation induced by LPS was inhibited by physalin B. The anti-inflammatory effects of physalin B could not be inhibited by mifepristone (RU486), the blocker of glucocorticoid receptor. In conclusion, physalin B can suppress inflammatory response to LPS in macrophages by inhibiting the production of inflammatory cytokines via NF-κB signaling.

A Novel Cytotoxic Physalin from Physalis angulata

Bioassay-guided fractionation from the whole plant of Physalis angulata led to the isolation of a novel physalin, 25-hydroxylisophysalin B (1), together with three megastigmane glucosides (2-4) and eight known physalins (5-12). The structure of compound 1 was elucidated by analysis of spectroscopic data. All of the compounds exhibited cytotoxic activities against MCF-7 human mammary cells and HepG2 human hepatoma cells.

Antiproliferative and Anti-inflammatory Withanolides from Physalis angulata

Sixteen new withanolides, physangulatins A-N (1-14) and withaphysalins Y and Z (15 and 16), as well as 12 known analogues, were isolated from the stems and leaves of Physalis angulata L. Their structures were established using extensive spectroscopic data analyses. The absolute configurations of 1 and 9 were assigned via X-ray crystallography. The isolated compounds were tested for their antiproliferative effects against human prostate cancer cells (C4-2B and 22Rvl), human renal carcinoma cells (786-O, A-498, and ACHN), and human melanoma cells (A375-S2), as well as inhibitory effects on NO production induced by LPS in macrophages. Compounds 9, 17, 20, 21, 25, and 27 showed antiproliferative effects against all tested cancer cells, with IC50 values of 0.18-7.43 μM. Compounds 3-5, 9-11, 17, 20-22, 24, 25, and 27 displayed inhibitory effects against NO production, with IC50 values of 1.36-11.59 μM.

Chemopreventive Agents from Physalis minima Function as Michael Reaction Acceptors

Background:

The fruits of some varieties of genus Physalis have been used as delicious fruits and functional food in the Northeast of China.

Materials and Methods:

To reveal the functional material basis, we performed bioactivity-guided phytochemical research and chemopreventive effect assay of the constituents from Physalis minima.

Results:

It was demonstrated that the ethyl acetate extract of P. minima L. (EEPM) had potential quinone reductase (QR) inducing activity with induction ratio (IR, QR induction activity) value of 1.47 ± 0.24, and glutathione binding property as potential Michael reaction acceptors (with an α, β-unsaturated ketone moiety). Furthermore, bioactivity-guided phytochemical research led eight compounds (1–8), which were elucidated as 3-isopropyl-5-acetoxycyclohexene-2-one-1 (1), isophysalin B (2), physalin G (3), physalin D (4), physalin I (5), physordinose B (6), stigmasterol-3-O-β-D-glucopyranoside (7) and 5α-6β-dihydroxyphysalin R (8) on the basis of nuclear magnetic resonance spectroscopy analyses and HRESIMS. Then, isophysalin B (2) and physordinose B (6) showed significant QR inducing activity with IR value of 2.80 ± 0.19 and 2.38 ± 0.46, respectively.

SUMMARY

An ultra-performance liquid chromatographic method with glutathione as the substrate was used to detect the Michael reaction acceptors in extracts of Physalis minima (EPM)

We investigated the chemical constituents of EPM guided by biological activity method

Isophysalin B (1) and physordinose B (6) showed strong quinone reductase inducing activity with induction ratio values of 2.80 ± 0.19 and 2.38 ± 0.46

This study generated useful information for consumers and many encourage researchers to utilize edible fruits from Physalis as a source of phytochemicals

Abbreviations used: EPM: Extracts of Physalis minima, EEPM: Ethyl acetate extract of Physalis minima L., GSH: Glutathione, MRAs: Michael reaction acceptors, QR: Quinone reductase.

Vitamin D inhibits the growth of and virulence factor gene expression by Porphyromonas gingivalis and blocks activation of the nuclear factor kappa B transcription factor in monocytes

BACKGROUND AND OBJECTIVE

Increasing evidence suggests that 1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), a fat-soluble secosteroid hormone, has a positive impact on periodontal health through diverse mechanisms. The present study was aimed at investigating the effect of 1,25(OH)2 D3 on the growth of and virulence factor gene expression by the periodontopathogenic bacterium Porphyromonas gingivalis. The effect of 1,25(OH)2 D3 on P. gingivalis-mediated activation of nuclear factor kappa B (NF-κB) transcription factor in monocytes was also assessed.

MATERIAL AND METHODS

A broth microdilution assay was used to determine the antibacterial activity of 1,25(OH)2 D3 . The modulation of virulence factor gene expression in P. gingivalis was assessed by quantitative reverse transcription-polymerase chain reaction. NF-κB activation was assessed using a human monocytic cell line stably transfected with a luciferase reporter containing NF-κB binding sites.

RESULTS

Minimal inhibitory concentrations of 1,25(OH)2 D3 against P. gingivalis ranged from 3.125 to 6.25 μg/mL. Moreover, a partial synergistic effect was observed when 1,25(OH)2 D3 was used in association with metronidazole. 1,25(OH)2 D3 attenuated the virulence of P. gingivalis by reducing the expression of genes coding for important virulence factors, including adhesins (fimA, hagA and hagB) and proteinases (rgpA, rgpB and kgp). 1,25(OH)2 D3 dose-dependently prevented P. gingivalis-induced NF-κB activation in a monocyte model.

CONCLUSION

Our study suggested that 1,25(OH)2 D3 selectively inhibits the growth of and virulence factor gene expression by P. gingivalis, in addition to attenuating NF-κB activation by this periodontopathogen. This dual action on P. gingivalis and the inflammatory response of host cells may be of particular interest with a view to developing a novel and inexpensive preventive/therapeutic strategy.

Cytotoxic activity of Piper cubeba extract in breast cancer cell lines

This study aimed to evaluate the cytotoxicity of a crude extract of Piper cubeba against normal and breast cancer cell lines. To prepare the extract, P. cubeba seeds were ground, soaked in methanol and dichloromethane and isolated by column chromatography. Fractions were tested for cytotoxicity effects on normal fibroblast (L929), normal breast (MCF-12A) and breast cancer cell lines (MCF-7, MDA-MB-468 and MDA-MB-231). The most effective fraction was selected for DNA fragmentation assay to detect apoptotic activity. The results showed that the methanolic crude extract had a higher cytotoxic activity against MDA-MB-468 and MCF-7 than a dichloromethane crude extract. Then, the methanolic crude extract was separated into six fractions, designated A to F. Fraction C was highly active against breast cancer cell lines with an IC50 value less than 4 μg/mL. Therefore, Fraction C was further separated into seven fractions, CA to CG. The 1H-NMR profile showed that Fraction CE was long chain hydrocarbons. Moreover, Fraction CE demonstrated the highest activity against MCF-7 cells with an IC50 value of 2.69 ± 0.09 μg/mL and lower cytotoxicity against normal fibroblast L929 cells with an IC50 value of 4.17 ± 0.77 μg/mL. Finally, DNA fragmentation with a ladder pattern characteristic of apoptosis was observed in MCF-7, MDA-MB-468, MDA-MB-231 and L929 cells, but not in MCF-12A cells.

Immune defence strategies of generalist and specialist insect herbivores

Ecological immunology examines the adaptive responses of animals to pathogens in relation to other environmental factors and explores the consequences of trade-offs between investment in immune function and other life-history traits. Among species of herbivorous insects, diet breadth may vary greatly, with generalists consuming a wide variety of plant families and specialists restricted to a few species. Generalists may thus be exposed to a wider range of pathogens exerting stronger selection on the innate immune system. To examine whether this produces an increase in the robustness of the immune response, we compared larvae of the generalist herbivore Heliothis virescens and the specialist Heliothis subflexa challenged by entomopathogenic and non-pathogenic bacteria. Heliothis virescens larvae showed lower mortality, a lower number of recoverable bacteria, lower proliferation of haemocytes and higher phagocytic activity. These results indicate a higher tolerance to entomopathogenic bacteria by the generalist, which is associated with a more efficient cell-mediated immune response by mechanisms that differ between these closely related species. Our findings provide novel insights into the consequences of diet breadth and related environmental factors, which may be significant in further studies to understand the ecological forces and investment trade-offs that shape the evolution of innate immunity.

Unprecedent aminophysalin from Physalis angulata

The 95% ethanol extract of the whole plant of Physalis angulata Linn. afforded one new skeletal physalin named aminophysalin A (1) and one new naturally occurring 5β-hydroxy-6a-chloro-5,6-dihydrophysalin B (2), together with five known physalins (3-7). Their structures were elucidated through MS, IR, NMR spectroscopy analyses and X-ray crystallography. Aminophysalin A (1) had an absolutely unusual structural feature in the chemistry of physalins with a nitrogen atom. Compounds 1-7 were evaluated for quinone reductase activities in hepa 1c1c7 cells. Physalin H (6) showed strong quinone reductase induction activity with IR (Induction ratio, QR induction activity) value of 3.74±0.02, using 4-bromoflavone as a positive control substance (2.17±0.01, 10 μg/mL), while compounds 1, 2, 3, 5 showed weak quinone reductase induction activity.

The rapid discovery and identification of physalins in the calyx of Physalis alkekengi L.var.franchetii (Mast.) Makino using ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry together with a novel three-step data mining strategy

Physalins, uniquely discovered from genus physalis, showed significant bioactivities in many aspects. It is therefore very important for the exploration of natural resources rich of physalins. However, there is no efficient approach for rapid discovery and identification of this class of compounds due to their structural complexity. To address the issue, the fragmentation pathways and correspondingly fragmentation rules of physalins in negative MS/MS mode were thoroughly investigated in this study using seven physalin standards. As a result, diagnostic ions for the rapid screening of physalins and classification of different types of physalins were determined based on their MS/MS fragmentation patterns. On top of that, an integrated approach using UHPLC-QTOF-MS/MS together with a novel three-step data mining strategy was developed for the systematic analysis of physalins in complex samples. Consequently, 46 physalins including 20 novel ones were efficiently discovered and identified from the crude extracts of Ph. alkekengi calyx. The present study laid a foundation for future study of different parts of Ph. alkekengi and other physalis species with regard to rapid discovery of novel physalins. In addition, this study provided a base for establishing a quality control method of the raw materials of Ph. alkekengi according to the profile of physalins.

Isolation, pharmacological activity and structure determination of physalin B and 5β,6β-epoxyphysalin B isolated from Congolese Physalis angulata L

Physalis angulata L., an annual herb from the Solanaceae family, is widely used in popular medicine in tropical countries to treat a variety of diseases. Two products, (X) and (Y), were isolated from a crude CH2Cl2 extract of dried Congolese Physalis angulata L. plants and crystallized from acetone for structure elucidation. Compound (X) corresponds to a physalin B dimer acetone solvate hydrate (2C28H30O9·C3H6O·0.22H2O), while compound (Y) crystallizes as a mixed crystal containing two physalin B molecules which overlap with 5β,6β-epoxyphysalin B, also known as physalin F, and one acetone molecule in the asymmetric unit (1.332C28H30O9·0.668C28H30O10·C3H6O). Antiplasmodial activity, cytotoxic activity and selectivity indices were determined for crude extracts and the two isolated products (X) and (Y).

Physalins B and F, seco-steroids isolated from Physalis angulata L., strongly inhibit proliferation, ultrastructure and infectivity of Trypanosoma cruzi

We previously observed that physalins have immunomodulatory properties, as well as antileishmanial and antiplasmodial activities. Here, we investigated the anti-Trypanosoma cruzi activity of physalins B, D, F and G. We found that physalins B and F were the most potent compounds against trypomastigote and epimastigote forms of T. cruzi. Electron microscopy of trypomastigotes incubated with physalin B showed disruption of kinetoplast, alterations in Golgi apparatus and endoplasmic reticulum, followed by the formation of myelin-like figures, which were stained with MDC to confirm their autophagic vacuole identity. Physalin B-mediated alteration in Golgi apparatus was likely due to T. cruzi protease perturbation; however physalins did not inhibit activity of the trypanosomal protease cruzain. Flow cytometry examination showed that cell death is mainly caused by necrosis. Treatment with physalins reduced the invasion process, as well as intracellular parasite development in macrophage cell culture, with a potency similar to benznidazole. We observed that a combination of physalins and benznidazole has a greater anti-T. cruzi activity than when compounds were used alone. These results indicate that physalins, specifically B and F, are potent and selective trypanocidal agents. They cause structural alterations and induce autophagy, which ultimately lead to parasite cell death by a necrotic process.

Physangulidines A, B, and C: three new antiproliferative withanolides from Physalis angulata L

Bioassay-directed fractionation of the whole plant of Physalis angulata L. afforded three new antiproliferative withanolides with an unusual carbon framework: physangulidines A (1), B (2), and C (3). Structures of the three isomeric withanolides were determined by a combination of HRMS, NMR spectroscopic, and X-ray crystallographic methods. Each has shown significant antiproliferative activity against DU145 prostate cancer cells. Physangulidine A (1) was further tested against a wide range of additional cancer cell lines and found to exhibit significant antiproliferative activity.

Isolation and characterization of a bactericidal withanolide from Physalis virginiana

BACKGROUND

Physalis virginiana (Virginia Groundcherry) is a member of the family Solenaceae. Several species of the Physalis genus have been used traditionally by American Indians as medicinal treatments.

MATERIALS AND METHODS

This study investigated the antibacterial activity of chemicals extracted from P. virginiana through antibacterial disc and cytotoxicity assays. Isolation and purification of an antimicrobial compound was achieved through flash chromatography and preparative HPLC. Finally, identification of chemical structure was determined from (1)H and (13)C NMR and MS.

RESULTS

Disc assays showed that crude ethanol extracts were effective antibacterial agents against one gram-negative and seven gram-positive bacterial strains. Cytotoxicity assays indicated that it is less toxic than gentamicin controls. Isolation of the active component showed it to be a relatively polar compound. (1)H and (13)C NMR chemical shifts together with HRMS indicated a similar structure to withanolides previously identified from Physalis angulata. HRMS analysis showed a molecular mass of 472.2857 which corresponds to a molecular formula C(28)H(40)O(6).

CONCLUSION

An antibacterial withanolide was isolated from P. virginiana using flash chromatography and HPLC separations. The chemical structure was determined by NMR and MS to be the withanolide physagulin V.

Genotoxic effects of (-)-cubebin in somatic cells of mice

(-)-Cubebin belongs to the dibenzylbutyrolactone lignan group, which is widely distributed in the plant kingdom. Because this compound shows interesting biological activities, it is extremely important to evaluate its possible genotoxic activity to allow its safe use in humans. Thus, the present study was performed to investigate the genotoxicity potential activity of (-)-cubebin assessed by two assays: micronucleus in bone marrow cells and comet test in peripheral blood leukocytes of Swiss mice. In the (-)-cubebin dose range-finding assays, the maximum tolerated dose was greater than 2000 mg kg(-1) . The compound was administered by an oral route at single doses of 250, 500 and 2000 mg kg(-1) body weight. Cytotoxicity was assessed by scoring 200 consecutive total polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE/NCE ratio). Under our experimental conditions, micronucleus and comet assays, respectively, showed that (-)-cubebin caused dose-related clastogenic and genotoxic effects in the somatic cells investigated. PCE/NCE ratio showed no cytotoxicity for the three doses of the compound. The data suggest caution in the ingestion of (-)-cubebin by humans, especially at high doses.

Antimicrobial activity of essential oils of Physalis angulata. L

The need for a reduction in drug resistance led to the investigation of Argemone Mexicana L. as an agent against Bacillus subtilis, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Candida stellatoidea and Candida torulopsis, using well diffusion and minimum inhibitory concentrations methods. The sensitivity of Bacillus Subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus to the essential oils of both the aerial and root parts were determined. Pseudomonas aeruginosa was resistant to the essential oil from both the aerial and root part of the plant. C. torulopsis, C. stellatoidea and C. albicans were susceptible to the essential oils from the aerial and root part of the plant. The minimum inhibitory concentrations ranging between 3.75 mg/ml and 4.0 mg/ml were recorded for Bacillus subtilis, Klebsiella pneumoniae by the aerial and the root extracts, but P. aeruginosa and S. aureus were not susceptible to the aerial and root extracts. The observed inhibition of selected bacteria and fungi by oils of Physalis angulata makes it a promising antimicrobial agent. This study justifies its uses for treatment of sores, cuts, intestinal and digestive problems and some skin-diseases often reported in folkloric medicine.

Antimicrobial activity of the extracts and physalin D from Physalis alkekengi and evaluation of antioxidant potential of physalin D

Physalis alkekengi L. (Solanaceae) is a popular plant in traditional European and Chinese folk medicine, and it has been reported to have many ethnopharmacological properties including antifungal, anti-cough, anti-inflammatory, analgesic, and febricide activities. Some active components from Physalis species have been investigated. However, no antimicrobial activity studies on extracts and physalins of P. alkekengi have been carried out. In this study, we attempted to identify the possible antimicrobial activities of the methanol extract from aerial parts of P. alkekengi and the dichloromethane extract from calyces of the plant. The extracts were tested against five Gram-positive and five Gram-negative bacteria and five Candida species by using disk diffusion and broth microdilution methods. The extracts were fractionated to isolate physalins using chromatographic techniques, and physalin D was isolated from the extracts. The structure of the compound was elucidated on the basis of (1)H-NMR spectroscopic study, and confirmed by comparison with a reference sample and literature data. Results indicated that all the extracts and physalin D were characterized by antibacterial action, especially against Gram-positive bacteria, with MIC values between 32 and 128 microg/mL. The methanol extract had moderate activity against fungi at MICs ranging from 128 to 512 microg/mL, but the dichloromethane extract and physalin D had low activity against fungi at MICs ranging from 256 to 512 microg/mL. Additionally, the antioxidant activity of physalin D was evaluated by qualitative DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and TBA (thiobarbituric acid) assays. Physalin D showed low antioxidant activity with an IC(50) value of >or= 10 +/- 2.1.

A pair of 3-epimeric physalins from Physalis alkekengi L. var. franchetii

A pair of new 3-epimeric steroids possessing a rare 13,14-seco-16,24-cycloergostane skeleton, 3alpha-methoxy-2,3-dihydro-4,7-didehydrophysalin B (1), and 3beta-methoxy-2,3-dihydro-4,7-didehydrophysalin B (2) were isolated from the 60% EtOH extract of the stems and leaves of Physalis alkekengi L. var. franchetii. Their structures were characterized on the basis of spectral evidence.