Antiprotozoal potential of Vismia species (Hypericaceae), medicinal plants used to fight cutaneous leishmaniasis.

ETHNOPHARMACOLOGICAL RELEVANCE: Species of Vismia (Hypericaceae), known in Brazil as "lacre", are commonly used in traditional Amazonian medicine for the treatment of skin lesions, including those caused by Leishmania infection. AIM OF THE STUDY: Hexane extracts from the leaves of Vismia cayennensis, V. gracilis, V. sandwithii and V. guianensis, as well as from the fruits of the latter, in addition to the anthraquinones vismiaquinone, physcion and chrysophanol isolated from these species were explored for their anti-promastigote and anti-amastigote activity on Leishmania amazonensis. MATERIALS AND METHODS: Extracts were prepared by static maceration with n-hexane. The compounds, isolated by chromatographic techniques, were identified by spectroscopic methods (1H and 13C NMR). Promastigotes of L.amazonensis were incubated with hexane extracts (1-50 µg/mL) or anthraquinones (1-50 µM) and the parasite survival analyzed. The action of compounds on reactive oxygen species (ROS) production, mitochondrial membrane potential, and membrane integrity of promastigotes were evaluated by flow cytometer, and the cytotoxicity on mammalian cells using MTT assay. Furthermore, the activity of compounds against amastigotes and nitric oxide production were also investigated. RESULTS: Vismiaquinone and physcion were obtained from the leaves of V. guianensis. Physcion, as well as chrysophanol, were isolated from V. sandwithii. Vismia cayennensis and V. gracilis also showed vismiaquinone, compound detected in lower quantity in the fruits of V. guianensis. All extracts were active against the parasite, corroborating the popular use. The greatest activity against promastigotes was achieved with V. guianensis extract (IC50 4.3 µg/mL), precisely the most used Vismia species for treating cutaneous leishmaniasis. Vismiaquinone and physcion exhibited relevant activity with IC50 12.6 and 2.6 µM, respectively. Moreover, all extracts and anthraquinones tested induced ROS production, mitochondrial dysfunction, membrane disruption and were able to kill intracellular amastigote forms, being worthy of further in vivo studies as potential antileishmanial drugs. CONCLUSIONS: The overall data achieved in the current investigation scientifically validate the traditional use of Vismia species, mainly V. guianensis, as an anti-Leishmania agent. Furthermore, the promising results presented here indicate species of Vismia as potentially useful resources of Brazilian flora for the discovery of therapeutic solutions for neglected diseases.

Study on the effect of processing methods on the total polyphenol, 2,3,5,4'-tetrahydroxystilben-2-O-ß-D-glucoside, and physcion contents in Fallopia multiflora Thunb. Haraldson root

Abstract This study investigated the changes in the ingredients in Fallopia multiflora Thunb. Haraldson (FMT) root after processing it with different methods such as soaking, stewing, and steaming or combined methods. The total polyphenol, 2,3,5,4'-tetrahydroxystilben-2-O-ß-D-glucoside (THSG), and physcion contents in FMT products after processing were determined using high-performance liquid chromatography (HPLC) and ultraviolet-visible (UV-VIS) methods. The results demonstrated that the processing method and time significantly affected the contents of polyphenol, THSG, and physcion. The physcion and total polyphenol content increased or decreased during processing depending upon the processing time, while the THSG content gradually decreased with an increase in the processing time. The content of physcion (a substance that can cause liver toxicity) was analysed, and the suitable conditions for processing of the FMT products were determined as initial soaking in rice swill for 24 h and subsequent stewing with black beans and water for 12 h

Inhibiting 6-phosphogluconate dehydrogenase enhances chemotherapy efficacy in cervical cancer via AMPK-independent inhibition of RhoA and Rac1.

BACKGROUND: The oxidative pentose phosphate pathway (PPP) is essential for cancer metabolism and growth. However, the contribution of 6-phosphogluconate dehydrogenase (6PGD), a key enzyme of PPP, to cervical cancer development remains largely unknown. METHODS: mRNA and protein levels of 6PGD were analyzed in cervical cancer cells and tissues derived from patients and compared to normal counterparts. Using cell culture system and xenograft mouse model, the functions of 6PGD in cervical cancer are determined and its molecular mechanism is analyzed. 6PGD inhibitor physcion and siRNA knockdown were used. RESULTS: In this work, we demonstrate that 6PGD is aberrantly upregulated and activated in cervical cancer cells and patient tissues compared to normal counterparts. Using different approaches and preclinical models, we show that 6PGD inhibition decreases growth and migration, and enhances chemosensitivity in cervical cancer. Mechanistically, inhibition of 6PGD activates AMP-activated protein kinase (AMPK) and decreases RhoA and Rac1 activities. AMPK depletion significantly reduces the effects of 6PGD inhibition in decreasing RhoA and Rac1 activities, growth and migration in cervical cancer cells. CONCLUSIONS: Our work is the first to demonstrate the aberrant expression of 6PGD and its predominant roles in cervical cancer cell growth and migration, via a AMPK-dependent activation. Our findings suggest 6PGD as a potential therapeutic target to enhance chemosensitivity in cervical cancer.

Inhibiting 6-phosphogluconate dehydrogenase selectively targets breast cancer through AMPK activation.

PURPOSE: 6-phosphogluconate dehydrogenase (6PGD), a key enzyme of the oxidative pentose phosphate pathway, is involved in tumor growth and metabolism. Although high 6PGD activity has been shown to be associated with poor prognosis, its role and therapeutic value in breast cancer remain unknown. METHODS: The levels and roles of 6PGD were analyzed in breast cancer cells and their normal counterparts. The underlying mechanisms of 6PGD's roles are also analyzed. RESULTS: We found that 6PGD is aberrantly activated in breast cancer as shown by its increased transcriptional and translational levels as well as enzyme activity in breast cancer tissues and cell lines compared to normal counterparts. Although similar degree of enzyme activity inhibition was achieved in both breast cancer and normal breast cells, 6PGD inhibition by siRNA-mediated knockdown or pharmacological inhibitor physcion is more effective in inhibiting growth and survival in breast cancer than normal breast cells. Moreover, inhibiting 6PGD significantly sensitizes breast cancer response to chemotherapeutic agents in in vitro cell culture system and in vivo xenograft breast cancer model. We further show that 6PGD inhibition activates AMPK and its downstream substrate ACC1, leading to reduction of ACC1 activity and lipid biosynthesis. AMPK depletion significantly reverses the inhibitory effects of physcion in breast cancer cells, confirming that 6PGD inhibition targets breast cancer cell via AMPK activation. CONCLUSIONS: Our work provides experimental evidence on the association of 6PGD with poor prognosis in breast cancer and suggests that 6PGD inhibition may represent a potential therapeutic strategy to augment chemotherapy efficacy in breast cancer.

Anthraquinones from the bark of Senna macranthera

2-acetyl physcion (2-acetyl-1,8-dihydroxy-6-methoxy-3-methyl-9,10-anthraquinone, 2), a rare anthraquinone, was isolated from Senna macranthera var. nervosa (Vogel) H.S. Irwin & Barneby (Fabaceae). The chemical structure was elucidated and all ¹H and 13C NMR chemical shifts were assigned by NMR one- (¹HNMR, {¹H}-13CNMR, and APT-13CNMR) and two (COSY, NOESY, HMQC and HMBC) dimensional of this natural compound. Furthermore, the minor anthraquinones chrysophanol (3), chrysophanol-8-methyl ether (4) and physcion (5) were characterized by GC-MS analysis. The occurrence of the anthraquinones 3-5 confirms that S. macranthera is a typical representative of the genus Senna.

2-acetil-fisciona (2-acetil-1, 8-di-hidróxi-6-metóxi-3-metil-9, 10-antraquinona, 2), uma antraquinona rara, foi isolada de Senna acranthera var. nervosa (Vogel) H.S. Irwin & Barneby (Fabaceae). estrutura química foi elucidada e todos os deslocamentos químicos de RMN ¹H e 13C foram atribuídos através de RMN uni- (RMN¹H, {¹H}-RMN-13C e APT-RMN13C) e bi- (COSY, NOESY, HMQC e HMBC) dimensional deste composto natural. Adicionalmente, as antraquinonas minoritárias crisofanol (3), crisofanol-8-metil éter (4) e fisciona (5) foram caraterizadas pela análise de CG-EM. A ocorrência das antraquinonas 3-5 confirma que S. macranthera é uma típica representante do gênero Senna.