Physalin F

Withanolides from dietary tomatillo suppress HT1080 cancer cell growth by targeting mutant IDH1.[Pubmed:33735687]

Bioorg Med Chem. 2021 Apr 15;36:116095.

Isocitrate dehydrogenase (IDH) is one key rate-limiting enzyme in the tricarboxylic acid cycle, which is related to various cancers. Tomatillo (Physalis ixocarpa), a special tomato, is widely consumed as nutritious vegetable in Mexico, USA, etc. As a rich source for withanolides, the fruits of P. ixocarpa were investigated, leading to the isolation of 11 type-A withanolides including 4 new ones (1 is an artificial withanolide). All these withanolides were evaluated for their inhibition on mutant IDH1 enzyme activity. Among them, Physalin F (11) exhibited potent enzyme inhibitory activity and binding affinity with mutant IDH1. It inhibits the proliferation of HT1080 cells by selectively inhibiting the activity of mutant IDH1. Since Ixocarpalactone A, another major type-B withanolide in this plant, could act on another energy metabolism target PHGDH, the presence of different types of withanolides in tomatillo and their synergistic effect could make it a potential antitumor functional food or drug.

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.[Pubmed:30946560]

ACS Chem Neurosci. 2019 Jun 19;10(6):2939-2955.

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.

YAP-dependent ubiquitination and degradation of beta-catenin mediates inhibition of Wnt signalling induced by Physalin F in colorectal cancer.[Pubmed:29789528]

Cell Death Dis. 2018 May 22;9(6):591.

Aberrant activation of Wnt/beta-catenin signalling is critical in the progression of human cancers, especially colorectal cancer (CRC). Therefore, inhibition of Wnt/beta-catenin signalling is a significant potential target for CRC therapy. Here, we identified for the first time that Physalin F (PF), a steroid derivative isolated from Physalis angulate, acts as an antagonist of Wnt/beta-catenin signalling. In vitro, PF decreased Wnt3a-induced TOPFlash reporter activity in HEK293T cells and promoted the formation of the beta-catenin destruction complex. Importantly, PF also inhibited Wnt/beta-catenin signalling and accelerated the degradation of beta-catenin in CRC cells. However, PF did not affect the stabilization of Axin or the interaction of beta-catenin with E-cadherin. Interestingly, we further found that PF promoted YAP binding to the beta-catenin destruction complex, which facilitated the ubiquitination and degradation of beta-catenin. Silencing and pharmacological inhibition of YAP reversed the formation of the beta-catenin destruction complex induced by PF, implying that YAP binding to the beta-catenin destruction complex was responsible for PF-mediated inhibition of Wnt/beta-catenin signalling. Furthermore, PF observably inhibited tumour growth by down-regulating beta-catenin in tumour-bearing mice. Collectively, our findings indicated that PF inhibited Wnt/beta-catenin signalling by accelerating the ubiquitination and degradation of beta-catenin in a YAP-dependent manner and therefore PF could be a novel potential candidate for CRC therapy.

Physalin F, a seco-steroid from Physalis angulata L., has immunosuppressive activity in peripheral blood mononuclear cells from patients with HTLV1-associated myelopathy.[Pubmed:27044821]

Biomed Pharmacother. 2016 Apr;79:129-34.

Human T-lymphotropic virus type 1 (HTLV-1) induces a strong activation of the immune system, especially in individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Physalin F is a secosteroid with potent anti-inflammatory and immunomodulatory activities. The present study aimed to investigate the effects of Physalin F on peripheral blood mononuclear cells (PBMC) of HAM/TSP subjects. A concentration-dependent inhibition of spontaneous proliferation of PBMC from HAM/TSP subjects was observed in the presence of Physalin F, as evaluated by (3)H-thymidine uptake. The IC50 for Physalin F was 0.97 +/- 0.11 muM. Flow cytometry analysis using Cytometric Bead Array (CBA) showed that Physalin F (10 muM) significantly reduced the levels of IL-2, IL-6, IL-10, TNF-alpha and IFN-gamma, but not IL-17A, in supernatants of PBMC cultures. Next, apoptosis induction was addressed by using flow cytometry to evaluate annexin V expression. Treatment with Physalin F (10 muM) increased the apoptotic population of PBMC in HAM/TSP subjects. Transmission electron microscopy analysis of PBMC showed that Physalin F induced ultrastructural changes, such as pyknotic nuclei, damaged mitochondria, enhanced autophagic vacuole formation, and the presence of myelin-like figures. In conclusion, Physalin F induces apoptosis of PBMC, decreasing the spontaneous proliferation and cytokine production caused by HTLV-1 infection.

Isolation, pharmacological activity and structure determination of physalin B and 5beta,6beta-epoxyphysalin B isolated from Congolese Physalis angulata L.[Pubmed:24311512]

Acta Crystallogr C. 2013 Dec 15;69(Pt 12):1557-62.

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 5beta,6beta-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).

Physalin F from Physalis minima L. triggers apoptosis-based cytotoxic mechanism in T-47D cells through the activation caspase-3- and c-myc-dependent pathways.[Pubmed:24051023]

J Ethnopharmacol. 2013 Oct 28;150(1):382-8.

ETHNOPHARMACOLOGICAL RELEVANCE: Physalin F (a secosteroid derivative), is well recognized as a potent anticancer compound from Physalis minima L., a plant that is traditionally used to treat cancer. However, the exact molecular anticancer mechanism remains to be elucidated. AIM OF THE STUDY: We have recently reported the apoptosis-based cytotoxic effect of the chloroform extract of this plant. Here, we investigated the cytotoxicity and possible cell death mechanism elicited by the active constituent, Physalin F on human breast T-47D carcinoma. MATERIALS AND METHODS: Cytotoxic-guided fractionation of the chloroform extract of Physalis minima has led to the isolation of Physalin F. The cytotoxicity activity was assayed using MTS assay. The effect of the compound to induce apoptosis was determined by biochemical and morphological observations through DeadEnd Colorimetric and annexin V assays, respectively, and RT-PCR analysis of mRNA expression of the apoptotic-associated genes. RESULTS: Cytotoxicity screening of Physalin F displayed a remarkable dose-dependent inhibitory effect on T-47D cells with lower EC50 value (3.60 mug/ml) than the crude extract. mRNA expression analysis revealed the co-regulation of c-myc- and caspase-3-apoptotic genes in the treated cells with the peak expression at 9 and 12h of treatment, respectively. This apoptotic mechanism is reconfirmed by DNA fragmentation and phosphatidylserine externalization. CONCLUSION: These findings indicate that Physalin F may potentially act as a chemopreventive and/or chemotherapeutic agent by triggering apoptosis mechanism via the activation of caspase-3 and c-myc pathways in T-47D cells.

Physalin F induces cell apoptosis in human renal carcinoma cells by targeting NF-kappaB and generating reactive oxygen species.[Pubmed:22815798]

PLoS One. 2012;7(7):e40727.

BACKGROUND: The aim of this study was to determine the molecular mechanisms of Physalin F, an effective purified extract of Physalis angulata L. (Solanacae), in renal carcinoma A498 cells. METHODOLOGY/PRINCIPAL FINDINGS: Physalin F was observed to significantly induce cytotoxicity of three human renal carcinoma A498, ACHN, and UO-31 cells in a concentration-dependent manner; this was especially potent in A498 cells. The Physalin F-induced cell apoptosis of A498 cells was characterized by MTT assay, nuclear DNA fragmentation and chromatin condensation. Using flow cytometry analysis, Physalin F induced A498 cell apoptosis as demonstrated by the accumulation of the sub-G1 phase in a concentration- and time-dependent manner. Moreover, Physalin F-mediated accumulation of reactive oxygen species (ROS) caused Bcl-2 family proteins, Bcl-2, and Bcl-xL degradation, which led to disruption of mitochondrial membrane potential and release of cytochrome c from the mitochondria into the cytosol. These effects were associated with induction of caspase-3 and caspase-9 activity, which led to poly(ADP-ribose) polymerase cleavage. However, the antioxidant N-acetyl-(L)-cysteine (NAC) and glutathione (GSH) resulted in the inhibition of these events and reversed Physalin F-induced cell apoptosis. In addition, Physalin F suppressed NF-kappaB activity and nuclear translocation of p65 and p50, which was reversed by NAC and GSH. CONCLUSION: Physalin F induced cell apoptosis through the ROS-mediated mitochondrial pathway and suppressed NF-kappaB activation in human renal cancer A498 cells. Thus, Physalin F appears to be a promising anti-cancer agent worthy of further clinical development.

Activity of physalin F in a collagen-induced arthritis model.[Pubmed:20681573]

J Nat Prod. 2010 Aug 27;73(8):1323-6.

The effects of Physalin F (1), a steroid derivative purified from Physalis angulata, were investigated in models of collagen-induced arthritis in DBA/1 mice and allergic airway inflammation in BALB/c mice. Oral treatment with 1 or dexamethasone caused a marked decrease in paw edema and joint inflammation when compared to vehicle-treated arthritic mice. In contrast, treatment with 1 had no effect in mice with allergic airway inflammation caused by ovalbumin immunization, whereas dexamethasone significantly reduced the number of inflammatory cells and eosinophils in the broncoalveolar lavage fluid and in lung sections of challenged mice. To further demonstrate that 1 acts through a mechanism different from that of glucocorticoids, a nuclear translocation assay was performed of the glucocorticoid receptor (GR) using COS-7 cells transfected with a plasmid encoding for a yellow fluorescent protein (YFP)-GR fusion protein. Untreated or treated cells with 1 had YFP staining mainly in the cytoplasm, whereas in dexamethasone-treated cells the YFP staining was concentrated in the nuclei. It is concluded that the mechanism of the immunosuppressive activity of Physalin F is distinct from that of the glucocorticoids.

Activity of physalins purified from Physalis angulata in in vitro and in vivo models of cutaneous leishmaniasis.[Pubmed:19454526]

J Antimicrob Chemother. 2009 Jul;64(1):84-7.

OBJECTIVES: We have previously demonstrated the immunomodulatory effects of physalins, secosteroids purified from Physalis angulata. Here we investigate the antileishmanial activity of physalins in vitro and in vivo in a model of cutaneous leishmaniasis. METHODS: The antileishmanial activity of physalins B, D and F was tested in Leishmania-infected macrophage cultures. For the in vivo studies, BALB/c mice were infected with Leishmania amazonensis subcutaneously in the ear pinna and treated with Physalin F by topical administration. RESULTS: Physalins B and F were able to reduce the percentage of Leishmania-infected macrophages and the intracellular parasite number in vitro at concentrations non-cytotoxic to macrophages. More importantly, topical treatment with Physalin F significantly reduced the lesion size, the parasite load and histopathological alterations in BALB/c mice infected with L. amazonensis. CONCLUSIONS: Our results demonstrate the potent antileishmanial activity of physalins, especially Physalin F, and suggest these molecules as the basis for the development of new therapeutic options for cutaneous leishmaniasis.