Inhibitory effect of extracts of latex of Calotropis procera against Candida albicans: A preliminary study

Synthesis of Silver Nanoparticles from Artemisia sieberiand Calotropis procera Medical Plant Extracts and their Characterization using SEM Analysis

ABSTRACT: The synthesis, characterization and application of biologically synthesized nanomaterials have become important research areas in nanotechnology, and the green synthesis of nanoparticles using plants is being increasingly studied largely because this approach is considered to lack the problems associated with conventional synthesis. Here we report the synthesis and characterization (using a scanning electron microscope) of silver nanoparticles (AgNPs) obtained using extracts of leaves of the medicinal plants, Artemisia sieberi and Calotropis procera. Scanning electron microscopy (SEM) studies revealed the characteristics of the synthesized nanoparticles which were confirmed by analyzing the excitation of surface plasmon resonance (SPR) using UV–vis spectrophotometer at 482 nm. SEM analysis of the synthesized Ag NPs clearly showed that the particles were predominantly spherical in shape, mostly aggregated and having a size around 8–20 nm. Finally, we consider that the nanoparticles synthesized in this study have potential for wide application in nanotechnology and nanomedicine.

Lipoxygenase inhibitors from the latex of Calotropis Procera

A radical-scavenging, guided phytochemical study of the latex of Calotropis Procera afforded five lignans (1-5), including a new one (4). The structural determination was accomplished using 1D- and 2D-NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and correlation with known compounds. Among the isolated compounds, acylated lignans (3-5) showed stronger antioxidant activity than non-acylated derivatives (1,2). Anti-inflammatory activity was evaluated by determining the inhibitory potential against 5- and 15-lipoxygenase enzymes. The highest anti-inflammatory activity was observed in compound 4, with IC50s values of 7.6 µM and 2.7 µM against 5-LOX and 15-LOX, respectively.

Cytotoxic cardenolides from the latex of Calotropis procera

Three new cardenolides (3, 9 and 10), along with eight known ones, were isolated from the latex of Calotropis procera. The structural determination was accomplished by the 1D- and 2D-NMR spectra as well as HRESIMS analysis. The growth inhibitory activity of the latex and its sub-fractions as well as isolated compounds was evaluated against human A549 and Hela cell lines. The results exhibited that latex had strong growth inhibitory activity with IC50s of (3.37 μM, A-549) and (6.45 μM, Hela). Among the four extracts (hexane, chloroform, ethyl acetate and aqueous), chloroform extract displayed the highest potential cytotoxic activity, with IC50s of (0.985 μM, A-549) and (1.471 μM, Hela). All the isolated compounds displayed various degrees of cytotoxic activity and the highest activity was observed by calactin (1) with IC50s values of (0.036 μM, A-549) and (0.083 μM, Hela). None of these isolated compounds exhibited good antimicrobial activity evaluated by determination of their MICs using the broth microdilution method against various infectious pathogens. The structure-activity relationships for cytotoxic activity were also discussed.

Antibacterial and phytochemical studies on Calotropis gigantia (L.) R. Br. latex against selected cariogenic bacteria

In vitro antibacterial potential of the chloroform, ethyl acetate, hexane, methanol and aqueous extracts of Calotropis gigantia (L.) R. Br. was evaluated by using five cariogenic bacteria, Actinomyces viscosus, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus mitis and Streptococcus mutans. Agar well diffusion method and minimum inhibitory concentration (MIC) were used for this purpose. The chloroform extracted fraction of latex showed inhibitory effect against S. mutans and L. acidophilus with MIC value of 0.032 and 0.52 mg/mL, respectively. Qualitative investigation on structure elucidation of bioactive compound using IR, NMR and GC-MS techniques revealed the presence of methyl nonanoate, a saturated fatty acid.