Direct sunlight enabled photo-biochemical synthesis of silver nanoparticles and their Bactericidal Efficacy: Photon energy as key for size and distribution control.

It is highly desirable to discover novel green synthesis methods for cheap and scalable synthesis of nanoparticles (NPs) to reduce the negative impact on the environment. But these approaches generally impose great challenge in controlling size, shape, and homogeneity of product NPs. Here in the present study, we report a novel approach enabling direct sunlight and oyster mushroom (Pleurotus citrinopileatus) extract for the photo-biochemical synthesis of Ag NPs. Sunlight of different wavelength was used to control the size and distribution of photo-biochemically produced NPs. Interestingly, it is observed that a smaller wavelength of sunlight produces smaller sized of NPs with a narrow size distribution. For examples; blue sunlight produces colloidal silver NPs with an average diameter of ~ 3.28 nm and 0.72 nm size distribution, while full sunlight produces comparatively larger sized (7.08 nm) NPs with wider (2.92 nm) size distribution. Since present approach uses only direct sunlight, freely available renewable energy source, a cheap biological extract as reducing and capping agent and cheap silver precursor, therefore it is an environment-friendly approach and can be used for the synthesis of NPs at industrial scale. Moreover, the size-dependent bactericidal effect has also been studied against pathogenic, Escherichia coli, bacteria. The minimum inhibitory concentration (MIC) 25 ppm and MBC 30 ppm have been observed for silver NPs of 3.28 nm average diameter.

A mechanism-based pharmacological evaluation of efficacy of Flacourtia indica in management of dyslipidemia and oxidative stress in hyperlipidemic rats.

BACKGROUND: Flacourtia indica (Burm. f.) Merr. is a medicinal plant indigenous to India and is broadly used worldwide for the treatment of a variety of health ailments. The present study was experimented on hyperlipidemic Charles Foster rats with the aim to explore the possible mechanism responsible for the antidyslipidemic activity of the hydromethanolic extract from F. indica leaves (FIL). METHODS: Hyperlipidemia was induced by a single intraperitoneal dose of Triton WR-1339 in Charles Foster rats. The plasma lipid levels were estimated in control and treated groups. The antioxidant potential of F. indica was assessed in both enzymatic and non-enzymatic systems. An acute toxicity study of high-performance liquid chromatography (HPLC)-fingerprinted extract was carried out in Swiss albino mice. RESULTS: The F. indica extract at a dose of 150 mg/kg significantly lowers the plasma level of total cholesterol (17%), triglycerides (13%), and phospholipids (16%) by increasing post-heparin lipolytic activity (19%) and lecithin-cholesterol-acyltransferase activity (20%) in Triton-induced hyperlipidemic rats. In addition, the F. indica extract showed significant in vitro antioxidant and anti-adipogenic activity. HPLC analysis indicates the presence of flavanones and flavones in the extract, and the extract was found to be non-toxic up to a dose of 2000 mg/kg body weight in the acute oral toxicity study. CONCLUSIONS: These finding suggest that F. indica holds significant potential in preventing clinical deterioration induced by dyslipidemia along with oxidative stress.

Antifilarial diarylheptanoids from Alnus nepalensis leaves growing in high altitude areas of Uttarakhand, India.

Lymphatic filariasis continues to be a major health problem in tropical and subtropical countries. A macrofilaricidal agent capable of eliminating adult filarial parasites is urgently needed. Platyphyllenone (A), alusenone (B), hirustenone (C) and hirsutanonol (D) are important biologically active diarylheptanoids present in Alnus nepalensis. In the present study, we report the antifilarial activity in diarylheptanoids isolated from the leaves of A. nepalensis. Out of four compounds (A-D) tested in vitro one has shown promising anti-filarial activity both in vitro and in vivo studies. This is the first ever report on antifilarial efficacy of a compound of the plant and warrants further studies around this scaffold. In addition, a sensitive, selective and robust densitometric high-performance thin-layer chromatographic method was developed and validated for the above four biomarker compounds. The separation was performed on silica gel 60F(254) high-performance thin layer chromatography plates using chloroform:methanol (9:1, v/v) as mobile phase. The quantitation of marker compounds was carried out using densitometric reflection/absorption mode at 600 nm after post-chromatographic derivatization using vanillin-sulfuric acid reagent. The method was validated for peak purity, precision, robustness, limit of detection (LOD) and quantitation (LOQ) etc., as per the International Conference on Harmonization (ICH) guidelines.

A promising anticancer and antimalarial component from the leaves of Bidens pilosa.

Bidens pilosa is used in folk medicine for various applications due to the presence of polyacetylenes, flavonoids, terpenoids, phenylpropanoids and others. Bioactivity-guided fractionation of different extracts of B. pilosa leaf showed potential in vitro anticancer and antimalarial activity and led to the identification of a potential marker compound, phenyl-1,3,5-heptatriyne. Erythrocyte osmotic fragility experiments revealed the various extracts as well as the marker component's toxicity profiles on normal blood cells.