Antiaflatoxigenic and antioxidant activities of Garcinia extracts.

The effect of hexane and chloroform extracts from the fruit rinds of Garcinia cowa and Garcinia pedunculata on the growth and aflatoxin production in Aspergillus flavus was studied using peanut powder as a model food system. The growth of A. flavus was completely inhibited by the hexane and chloroform extracts from G. cowa and chloroform extract from G. pedunculata at 3000 ppm concentration, which was considered as the minimum inhibitory concentration (MIC). The MIC for the hexane extract of G. pedunculata was at 4000 ppm. Both the extracts from G. cowa inhibited aflatoxin B1 production upto 100% at a lower concentration of 2000 ppm. It was observed that, at lower concentration of the extracts from G. cowa and G. pedunculata, the degree of inhibition of aflatoxin production was much higher than the inhibition of fungal growth. The hexane and chloroform extracts from G. cowa and G. pedunculata were also studied for their antioxidant capacity by the formation of phosphomolybdenum complex at 100 ppm concentration and reducing power by potassium ferricyanide reduction method at various concentrations. Hexane and chloroform extracts from G. cowa showed higher antioxidant capacity than G. pedunculata extracts. Similarly, both the extracts from G. cowa showed higher reducing power than the extracts from G. pedunculata. The antiaflatoxigenic activities of the extracts from G. cowa and G. pedunculata may be due to their effective antioxidative properties, which could suppress the biosynthesis of aflatoxin.

Determination of organic acids in leaves and rinds of Garcinia indica (Desr.) by LC.

Organic acids in leaves and rinds of Garcinia indica (Kokam) were determined by high-performance liquid chromatography. The major organic acid in leaves and rinds has been found to be (-)-hydroxycitric acid present to the extent of 4.1-4.6 and 10.3-12.7%, respectively, by isocratic elution with 8 mM sulfuric acid as mobile phase with a flow rate of 1.0 ml/min using UV detection at 210 nm. Hydroxycitric acid lactone and citric acid are present in leaves and rinds in minor quantities. This method has been shown to be very reproducible with the coefficient of variation ranging from 2.8 to 4.2%. This is the first report on the composition of organic acids in the leaves and rinds of G. indica by HPLC.

Chemistry and biochemistry of (-)-hydroxycitric acid from Garcinia.

(-)-Hydroxycitric acid [(-)-HCA] is the principal acid of fruit rinds of Garcinia cambogia, Garcinia indica, and Garcinia atroviridis. (-)-HCA was shown to be a potent inhibitor of ATP citrate lyase (EC 4.1.3.8), which catalyzes the extramitochondrial cleavage of citrate to oxaloacetate and acetyl-CoA: citrate + ATP + CoA --> acetyl-CoA + ADP + P(i) + oxaloacetate. The inhibition of this reaction limits the availability of acetyl-CoA units required for fatty acid synthesis and lipogenesis during a lipogenic diet, that is, a diet high in carbohydrates. Extensive animal studies indicated that (-)-HCA suppresses the fatty acid synthesis, lipogenesis, food intake, and induced weight loss. In vitro studies revealed the inhibitions of fatty acid synthesis and lipogenesis from various precursors. However, a few clinical studies have shown controversial findings. This review explores the literature on a number of topics: the source of (-)-HCA; the discovery of (-)-HCA; the isolation, stereochemistry, properties, methods of estimation, and derivatives of (-)-HCA; and its biochemistry, which includes inhibition of the citrate cleavage enzyme, effects on fatty acid synthesis and lipogenesis, effects on ketogenesis, other biological effects, possible modes of action on the reduction of food intake, promotion of glycogenesis, gluconeogenesis, and lipid oxidation, (-)-HCA as weight-controlling agent, and some possible concerns about (-)-HCA, which provides a coherent presentation of scattered literature on (-)-HCA and its plausible mechanism of action and is provocative of further research.

Chemical composition of turmeric oil--a byproduct from turmeric oleoresin industry and its inhibitory activity against different fungi.

Curcumin, the yellow coloring pigment of turmeric is produced industrially from turmeric oleoresin. The mother liquor after isolation of curcumin from oleoresin known as curcumin removed turmeric oleoresin (CRTO) was extracted three times with n-hexane at room temperature for 30 min to obtain turmeric oil. The turmeric oil was subjected to fractional distillation under vacuum to get two fractions. These fractions were tested for antifugal activity against Aspergillus flavus, A. parasiticus, Fusarium moniliforme and Penicillium digitatum by spore germination method. Fraction II was found to be more active. The chemical constituents of turmeric oil, fraction I and fraction II were determined by GC and identified by GC-MS. Aromatic turmerone, turmerone and curlone were major compounds present in fraction II along with other oxygenated compounds.

Chemical composition of the flower oil of Cinnamomum zeylanicum blume.

The steam-distilled oil of cinnamon (Cinnamomum zeylanicum) flowers was analyzed by GC and GC-MS. It consists of 23% hydrocarbons and 74% oxygenated compounds. A total of 26 compounds constituting approximately 97% of the oil were characterized. (E)-Cinnamyl acetate (41.98%), trans-alpha-bergamotene (7.97%), and caryophyllene oxide (7.2%) are found to be major compounds. This is the first report on the chemical composition of the flower oil of Cinnamomum zeylanicum.

Antibacterial activity of Citrus reticulata peel extracts.

Citrus peels were successively extracted with hexane, chloroform and acetone using a soxhlet extractor. The hexane and chloroform extracts were fractionated into alcohol-soluble and alcohol-insoluble fractions. These fractions were tested against different gram positive and gram negative bacteria. The EtOH-soluble fraction was found to be most effective. Fractionation of EtOH-soluble fraction on silica gel column yielded three polymethoxylated flavones, namely desmethylnobiletin, nobiletin and tangeretin. Their structures were confirmed by UV, 1H, 13C NMR and mass spectral studies. The findings indicated a potential of these natural compounds as biopreservatives in food applications.

Antibacterial activity of turmeric oil: a byproduct from curcumin manufacture.

Curcumin, the yellow color pigment of turmeric, is produced industrially from turmeric oleoresin. The mother liquor after isolation of curcumin from oleoresin contains approximately 40% oil. The oil was extracted from the mother liquor using hexane at 60 degrees C, and the hexane extract was separated into three fractions using silica gel column chromatography. These fractions were tested for antibacterial activity by pour plate method against Bacillus cereus, Bacillus coagulans, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Fraction II eluted with 5% ethyl acetate in hexane was found to be most active fraction. The turmeric oil, fraction I, and fraction II were analyzed by GC and GC-MS. ar-Turmerone, turmerone, and curlone were found to be the major compounds present in these fractions along with other oxygenated compounds.

Limonoids from Citrus reticulata and their moult inhibiting activity in mosquito Culex quinquefasciatus larvae.

Three limonoids, namely limonin, nomilin and obacunone, were isolated from the seeds of Citrus reticulata [Blanco Coorg Mandarin]. Their structures were confirmed by spectroscopic studies. With 4th instar larvae of mosquito Culex quinquefasciatus, the EC50 for inhibition of adult emergence was 6.31, 26.61 and 59.57 ppm for obacunone, nomilin and limonin, respectively. The pattern of mortality at around the EC50 levels was indicative of moult inhibiting activity. The efficacy of a limonoid enriched fraction was similar to that of limonin, probably due to the high content (70%) of limonin.