Tigliane-Type Diterpene Esters from the Fruits of Shirakiopsis indica and Their Anti-HIV Activity.

Four new diterpene esters, shirakindicans A-D (1-4), along with eight related known diterpene esters (5-12), were isolated from the fruits of the Bangladeshi medicinal plant Shirakiopsis indica. The structures of 1-4 were elucidated by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Shirakindican A (1) was assigned as a tigliane-type diterpene ester possessing an unusual 6ß-hydroxy-1,7-dien-3-one structure, while shirakindican B (2) exhibits a tiglia-1,5-dien-3,7-dione structure. The anti-HIV activities of the isolated diterpene esters were evaluated and showed significant activities for sapintoxins A (5) and D (11), with EC50 values of 0.0074 and 0.044 µM, respectively, and TI values of 1 100 and 5 290. Sapatoxin A (12) also exhibited anti-HIV activity with an EC50 value of 0.13 µM and a TI value of 161.

Triterpenoids from the fruits of Azadirachta indica (Meliaceae).

Four new triterpenoids, indicalilacols A-D (1-4), were isolated from the MeOH extract of the fruits of Azadirachta indica, including a new 19(10→9ß)abeo-tirucallane derivative, two new tirucallane-type triterpenoids, and a new euphane-type triterpenoid, along with three known tirucallane-type triterpenoids. Their structures were elucidated on the basis of spectroscopic analyses. The absolute configuration of 2 was elucidated by the chemical conversion of 2 into 21-oxo-melianodiol 24,25-acetonide. Compounds 2, 6-8 exhibited moderate cytotoxicity against three human cancer cell lines, including multidrug-resistant (MDR) cancer cells (KB-C2). Although compound 5 was not cytotoxic against any of the tested cancer cell lines, 5 showed cytotoxicity against KB-C2 cells in the presence of 2.5 µM colchicine, suggesting that 5 might have an MDR-reversal effect.

New α-glucosides of caffeoyl quinic acid from the leaves of Moringa oleifera Lam.

Two new caffeoyl quinic acid α-glucosides, together with three known caffeoyl quinic acids and five known flavonoid glucosides, were isolated from the leaves of Moringa oleifera Lam. The structures of the new compounds were elucidated as 4-O-(4'-O-α-D-glucopyranosyl)-caffeoyl quinic acid (1) and 4-O-(3'-O-α-D-glucopyranosyl)-caffeoyl quinic acid (2) by spectroscopic analyses.

Acute and sub-acute toxicity of an insect pheromone, N-heneicosane and combination with insect growth regulator, diflubenzuron, for establishing no observed adverse effect level (NOAEL).

Aedes aegypti mosquito is one of the most notorious vectors of dangerous diseases like dengue hemorrhagic fever and chikangunya. One method of control of the vectors is by the use of semiochemicals or pheromones. The pheromone n-heneicosane (C21) has been proved to be effective in attracting the female Aedes aegypti to lay eggs in the treated water and the growth of the larva is controlled by insect growth regulator diflubenzuron (DB). This study was planned to assess the safety of C21 alone and the combination with DB. Acute toxicity tests were carried out using two doses, viz., 1600 and 3200 mg/kg and two routes of exposure oral and intra-peritoneal. Dermal toxicity test was carried out in both male and female rats at the dose of 3200 mg/kg. Primary skin irritation test was carried out in rabbits. Sub-acute (90 days) dermal toxicity studies in male and female rats at the dose of 1 and 2 mg/kg via the per-cutaneous route were also studied. Sub-acute (90 days) toxicity test through the oral route was carried out, at doses 125, 250 and 500 mg/kg in male and female rats. The calculated LD50 by ip route and dermal route was more than 5 g/kg in mouse and rats of both the sexes. In the primary skin irritation test no significant changes were noted. In the sub-acute toxicity studies even 500 mg/kg dose was not able to produce toxic response in rats when they were dosed daily for 90 days. The established no observed adverse effect level (NOAEL) was more than 500 mg/kg.

Comparative effects of insect repellent N,N-diethylbenzamide, N,N-diethylphenylacetamide, and N,N-diethyl-3- methylbenzamide aerosols on the breathing pattern and respiratory variables in mice.

Comparative inhalation toxicity studies of aerosols of insect repellents N,N-diethylbenzamide (DEB), N,N-diethylphenylacetamide (DEPA), and N,N-diethyl-3-methylbenzamide (DEET) were carried out in mice. The respiratory pattern was monitored using a computer program that recognizes the modifications of the breathing pattern. Exposure to the aerosols caused a dose-dependent decrease in normal breath, with an increase in airway obstruction. All the three insect "sensilla irritants" showed no significant mammalian sensory irritation. The acute LC(50) value for a 4-h exposure of DEB, DEPA, and DEET aerosols in male mice was found to be >2.5 g/m(3), 1714 mg/m(3), and 1369 mg/m(3), respectively. Irreversible depression in respiratory frequency was observed after exposure to DEB aerosol at a concentration of 277 mg/m(3) and above, which did not revert back to normal level even after aerosol exposure was stopped. At a concentration of 156 mg/m(3) of DEB, no respiratory depression was observed. DEPA and DEET caused no depression in respiratory frequency up to a concentration 1292 and 950 mg/m(3), respectively. Hence the two insect repellents DEET and DEPA do not cause any harmful effect to the respiratory parameters in acute exposure, showing that they are more suitable chemicals to be used as insect repellents as compared to DEB.