Taxoids-rich extract from Taxus wallichiana alleviates high-fat diet-induced insulin resistance in C57BL/6 mice through inhibition of low-grade inflammation.

The needle powder of Taxus wallichiana is in use for the management of diabetes and inflammation-related complications in the Indian and Chinese Systems of Traditional Medicine but the lack of proper pharmacological intervention has prompted us to investigate the pharmacological mechanism against inflammation-induced insulin resistance in high-fat diet-fed C57BL/6 mice. Hexane (Tw-H), chloroform (Tw-C), and ethyl acetate (Tw-EA) extracts were prepared from a needle of T. wallichiana and its effect on glucose uptake against TNF-α-induced insulin resistance in skeletal muscle cells was studied. Among all, Tw-EA extract has shown promising glucose uptake potential. Tw-EA treatment is also able to decrease the lipid accumulation in adipocytes. Chemical signature of Tw-EA using HPLC showed the presence of taxoids. Efficacy of taxoids-rich extract from T. wallichiana (Tw-EA) was further validated in in vivo system against high-fat diet (HFD)-induced insulin resistance in C57BL/6 mice. Oral treatment of Tw-EA showed significant reduction in blood glucose, pro-inflammatory cytokine production and body weight gain when compared with vehicle-treated HFD-induced insulin resistance in C57BL/6 mice. Histopathology and immunohistochemistry study in skeletal muscle and adipose tissue revealed that oral treatment of Tw-EA is able to reduce the infiltration of inflammatory cells in skeletal muscles, ameliorate the hypertrophy in adipose tissue and upregulate the GLUT4 protein expression. Treatment with Tw-EA significantly up-regulated mRNA expression of insulin signaling pathway (IRS-1, PI3K, AKT, GLUT 4). This study suggested the beneficial effect of taxoids-rich extract from Taxus wallichiana against the inflammation-associated insulin resistance condition.

Chemical composition and antimicrobial activity of the leaf essential oil of Ravenia spectabilis Engl. (Rutaceae).

Ravenia spectabilis Engl. belongs to the family Rutaceae is known to possess several biologically active phytomolecules. This study was planned to investigate the chemical composition and antimicrobial activity of the leaf essential oil of R. spectabilis. The hydrodistillation of fresh leaves of R. spectabilis gave 0.19 ± 0.02% essential oil. The resulting essential oil was analysed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Altogether, thirty-one constituents forming 97.6 ± 1.72% of the total oil composition were identified. Major components of the oil were sabinene (60.8 ± 0.36%), α-pinene (5.4 ± 0.30%), myrcene (4.8 ± 0.25%), δ-3-carene (4.7 ± 0.62%) and ß-pinene (4.3 ± 0.17%). The in-vitro antimicrobial potential of the oil was examined against eight human pathogenic bacterial and fungal strains. The essential oil showed significant activity against Staphylococcus aureus, Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, Candida albicans, and Candida kefyr. This is the first report on R. spectabilis leaf essential oil composition and its antimicrobial activity. The essential oil could be a promising natural source of sabinene and antimicrobial for developing new phytotherapeutics.

New Insights into the Chemical Composition, Pro-Inflammatory Cytokine Inhibition Profile of Davana (Artemisia pallens Wall. ex DC.) Essential Oil and cis-Davanone in Primary Macrophage Cells.

Artemisia pallens Wall. ex DC., popularly known as davana, has gained considerable attention because of its unique fragrance, high economic value, and pharmacological properties. The compositional complexity of davana essential oil (DO) has been a challenge for quality control. In this study, the chemical profile of DO was developed using polarity-based fractionation and a combination of gas chromatographic (GC-FID), hyphenated chromatographic (GC/MS), and spectroscopic (Fourier-Transform Infra-Red, 1D, 2D-Nuclear Magnetic Resonance) techniques. The analysis led to the identification of ninety-nine compounds. Major components of the DO were cis-davanone (D3, 53.0 %), bicyclogermacrene (6.9 %), trans-ethyl cinnamate (4.9 %), davana ether isomer (3.4 %), spathulenol (2.8 %), cis-hydroxy davanone (2.4 %), and trans-davanone (2.1 %). The study led to identifying several co-eluting novel minor components, which could help determine the authenticity of DO. The rigorous column-chromatography led to the isolation of five compounds. Among these, bicyclogermacrene, trans-ethyl cinnamate, and spathulenol were isolated and characterized by spectroscopic methods for the first time from DO. Pharmacological profile revealed that the treatment of DO and D3 inhibited the production of pro-inflammatory cytokines (TNF-α, IL-6) induced by lipopolysaccharide (LPS) in primary macrophages without any cytotoxic effect after administration of their effective concentrations. The result of this study indicates the suitability of DO and D3 for further investigation for the treatment of chronic skin inflammatory conditions.