GC and GC/MS analysis of essential oil composition of the endemic Soqotraen Leucas virgata Balf.f. and its antimicrobial and antioxidant activities.

Leucas virgata Balf.f. (Lamiaceae) was collected from the Island Soqotra (Yemen) and its essential oil was obtained by hydrodistillation. The chemical composition of the oil was investigated by GC and GC-MS. Moreover, the essential oil was evaluated for its antimicrobial activity against two Gram-positive bacteria, two Gram-negative bacteria, and one yeast species by using broth micro-dilution assay for minimum inhibitory concentrations (MIC) and antioxidant activity by measuring the scavenging activity of the DPPH radical. The investigation led to the identification of 43 constituents, representing 93.9% of the total oil. The essential oil of L. virgata was characterized by a high content of oxygenated monoterpenes (50.8%). Camphor (20.5%) exo-fenchol (3.4%), fenchon (5.4%), and borneol (3.1%) were identified as the main components. Oxygenated sesquiterpenes were found as the second major group of compounds (21.0%). ß-Eudesmol (6.1%) and caryophyllene oxide (5.1%) were the major compounds among oxygenated sesquiterpenes. The results of the antimicrobial assay showed that the oil exhibited a great antibacterial activity against the tested S. aureus, B. subtilis, and E. coli. No activity was found against P. aeruginosa and C. albicans. Moreover, the DPPH-radical scavenging assay exhibited only a moderate antioxidant activity (31%) for the oil at the highest concentration tested (1 mg/mL).

Phoenix dactylifera L. spathe essential oil: chemical composition and repellent activity against the yellow fever mosquito.

Date palm, Phoenix dactylifera L. (Arecaceae), grows commonly in the Arabian Peninsula and is traditionally used to treat various diseases. The aim of the present study was to identify chemical composition of the essential oil and to investigate the repellent activity. The essential oil of P. dactylifera was obtained by hydrodistillation from the spathe, a specialized leaf structure that surrounds the pollinating organs of the palm. The oil was subsequently analyzed by GC-FID and GC-MS. The oil showed promising repellent activity against yellow fever mosquito - Aedes aegypti. Sixteen components were characterized, constituting 99% of the oil. The main components were 3,4-dimethoxytoluene (73.5%), 2,4-dimethoxytoluene (9.5%), ß-caryophyllene (5.5%), p-cresyl methyl ether (3.8%), and caryophyllene oxide (2.4%). The minimum effective dosage (MED) for repellency for the P. dactylifera oil was 0.051mg/cm(2), which had moderately lower potency compared to reference standard N,N-diethyl-3-methylbenzamide, DEET (0.018mg/cm(2)) in the "cloth patch assay". The five major compounds were individually assayed for repellency to determine to what extent each is responsible for repellency from the oil. 3,4-Dimethoxytoluene and 2,4-dimethoxytoluene showed the best repellent activity with the same MED value of 0.063mg/cm(2), respectively. The results indicate that these two constituents which comprise a large proportion of the P. dactylifera oil (83%) are likely responsible for the observed repellent activity. In this aspect, the P. dactylifera spathe oil is a sustainable, promising new source of natural repellents.

Edible oils for liver protection: hepatoprotective potentiality of Moringa oleifera seed oil against chemical-induced hepatitis in rats.

In the present study, in vitro antioxidant, antioxidative stress and hepatoprotective activity of Moringa oleifera Lam. seed oil (Ben oil; BO) was evaluated against carbon tetrachloride (CCl(4) ) induced lipid peroxidation and hepatic damage in rats. The oil at 0.2 and 0.4 mL/rat was administered orally for 21 consecutive days. The substantially elevated serum enzymatic (GOT, GPT, ALP, GGT) and bilirubin levels were significantly restored towards normalization by the oil. There was a significant elevation in the level of malondialdehyde (MDA), non-protein sulfhydryl (NP-SH), and total protein (TP) contents in the liver tissue. The results obtained indicated that BO possesses potent hepatoprotective action against CCl(4) -induced hepatic damage by lowering liver marker enzymes, MDA concentration, and elevating NP-SH and TP levels in liver tissue. The biochemical observations were supplemented with histopathological examination of rat liver. The results of this study showed that treatment with Ben oil or silymarin (as a reference) appears to enhance the recovery from hepatic damage induced by CCl(4) . The pentobarbital induced narcolepsy prolongation in mice was retarded by the Ben oil. Acute toxicity test in mice showed no morbidity or mortality. In vitro DPPH radical scavenging and ß-carotene-linolic acid assay tests of the BO exhibited a moderate antioxidant activity in both tests used. The possible mechanism(s) of the liver protective activity of Ben oil activity may be due to free radical scavenging potential caused by the presence of antioxidant component(s) in the oil. Consequently, BO can be used as a therapeutic regime in treatment of some hepatic disorders.