Investigation of inclusion complexes of citronella oil, citronellal and citronellol with β-cyclodextrin for mosquito repellent

The aim of this study was to prepare the inclusion complexes of citronella oil, citronellal or citronellol with β-cyclodextrin and evaluate their physicochemical properties using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). A kneading method was employed to prepare the inclusion complexes and weight ratios of each of the active substance to β-cyclodextrin were 1:1 (1:1 CPX) and 1:2 (1:2 CPX). For comparison purposes, physical mixtures of these active compounds and β-cyclodextrin were also prepared and investigated. Unlike the physical mixtures, the SEM technique revealed drastic changes in the shapes and morphologies of the particles for the inclusion complexes. Furthermore, the FTIR and DSC results seemed to reveal some interactions between the active substance and β-cyclodextrin. The o/w lotions, which contained 10% w/w citronella oil (normal citronella oil; 1:1 CPX or 1:2 CPX), were formulated using Cremophors as emulsifiers. With modified Franz diffusion cell and synthetic membrane, the release rates of citronella oil from the lotions containing the inclusion complexes were significantly lower than that from the prepared lotion containing normal citronella oil. The mosquito (Aedes aegypti) repellent efficacy of the lotions containing citronella oil, citronellal or citronellol (both normal and inclusion complexes) was further evaluated by human-bait technique. The highest mosquito repellent activity was observed in the formulation which contained citronella oil–β-cyclodextrin inclusion complex at weight ratio of 1:1.     

Rubber products prepared from silica modified by radiation-induced admicellar polymerization

Unmodified silica, silica modified with Si69, silica modified by thermal admicellar polymerization and silica modified by radiation-induced admicellar polymerization were applied as rubber reinforcement. Mechanical properties of these different rubber formulae were subsequently tested. The results revealed that the mechanical properties of rubber reinforced with silica modified by admicellar polymerization were superior to those reinforced with unmodified silica or silica modified with Si69. As for the silica modified by admicellar polymerization, cetyltrimethyl ammonium bromide (CTAB) proved to be the most effective surfactant, compared to dodecyltrimethyl ammonium bromide (DTAB) and tetradecyltrimethyl ammonium bromide (TTAB).     

The Enhancing Immune Response and Anti-Inflammatory Effects of Caulerpa lentillifera Extract in RAW 264.7 Cells

Background: Caulerpa lentillifera (CL) is a green seaweed, and its edible part represents added value as a functional ingredient. CL was dried and extracted for the determination of its active compounds and the evaluation of its biological activities. The major constituents of CL extract (CLE), including tannic acid, catechin, rutin, and isoquercetin, exhibited beneficial effects, such as antioxidant activity, anti-diabetic activity, immunomodulatory effects, and anti-cancer activities in in vitro and in vivo models. Whether CLE has an anti-inflammatory effect and immune response remains unclear. Methods: This study examined the effect of CLE on the inflammatory status and immune response of lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and the mechanisms involved therein. RAW264.7 cells were treated with different concentrations of CLE (0.1–1000 µg/mL) with or without LPS (1 µg/mL) for 24 h. Expression and production of the inflammatory cytokines, enzymes, and mediators were evaluated. Results: CLE suppressed expression and production of the pro-inflammatory cytokines IL-6 and TNF-α. Moreover, CLE inhibited expression and secretion of the inflammatory enzyme COX-2 and the mediators PGE2 and NO. CLE also reduced DNA damage. Furthermore, CLE stimulated the immune response by modulating the cell cycle regulators p27, p53, cyclin D2, and cyclin E2. Conclusions: CLE inhibits inflammatory responses in LPS-activated macrophages by downregulating inflammatory cytokines and mediators. Furthermore, CLE has an immunomodulatory effect by modulating cell cycle regulators.     

A novel 29-nor-3,4-seco-friedelane triterpene and a new guaiane sesquiterpene from the roots of Phyllanthus oxyphyllus

An unusual 29-nor-3,4-seco-friedelan-4(23),20(30)-dien-3-oic acid and a new 5-hydroxy-6,9-epoxyguaiane have been isolated along with other rare terpenes and lignans from Phyllanthus oxyphyllus roots. Their structures were elucidated from spectroscopic data. The radical scavenging properties of some of these compounds were evaluated. seco-Isolariciresinol showed strong antioxidant activity (IC₅₀ 0.017±0.001 mM).