Study on the volatile oil contents of Annona glabra L., Annona squamosa L., Annona muricata L. and Annona reticulata L., from Vietnam.

The volatile compounds identified from four species of Annona from Vietnam are being reported. The oils were obtained from aliquots of plant samples by steam distillation and subjected to GC and GC-MS analysis. The main compounds of Annona glabra L., were ß-caryophyllene (21.5%) germacrene D (17.7%), α-cadinol (5.4%) and ß-elemene (5.2%). Annona squamosa L., comprised mainly of α-pinene (1.0-11.9%), limonene (0.8-11.7%), ß-cubebene (0.5-13.0%), ß-caryophyllene (11.6-24.5%), spathulenol (0.8-9.0%), caryophyllene oxide (1.0-10.6%) and α-cadinol (3.3-7.8%). The significant constituents of Annona muricata L., were α-pinene (9.4%), ß-pinene (20.6%), ρ-mentha-2,4(8)-diene (9.8%), ß-elemene (9.1%) and germacrene D (18.1%). However, camphene (0.2-6.6%), α-copaene (2.0-7.3%), ß-elemene (5.9-16.6%), ß-caryophyllene (8.3-14.9%), ß-bisabolene (0.4-10.2%), δ-cadinene (1.7-4.8%) and germacrene D (9.3-22.8%) were the main compounds common to samples of Annona reticulata L. There were significant amounts of sabinene (11.2% and 2.7%; leaf and stem bark) and bicycloelemene (9.6% and 6.1%; stem and bark).

Modes of inhibition of α -amylase and α -glucosidase by aqueous extract of Morinda lucida Benth leaf.

Diabetes mellitus is a metabolic disorder of glucose metabolism. The management of blood glucose level is the hallmark in the treatment of this disease. This may be achieved through the use of oral hypoglycemic drugs such as biguanides, insulin secretagogues, and α-glucosidase inhibitors. The purpose of the present study was to investigate the inhibitory effect of Morinda lucida leaf extracts on the activities of α-amylase and α-glucosidase. This was performed using α-amylase from Aspergillus oryzae and α-glucosidase from Saccharomyces cerevisiae. Aqueous extract of Morinda lucida gave the highest percentage yield (9.99%) of the plant out of the three extracts (compared to acetone and ethanolic extracts) and possesses the highest inhibitory activity against α-amylase (IC50 value of 2.30 mg/mL) and α-glucosidase (IC50 value of 2.00 mg/mL). Kinetic analysis revealed that the aqueous extract of this plant leaf inhibited the α-amylase competitively but displayed mixed noncompetitive mode of inhibition towards α-glucosidase. It can be concluded that aqueous extract of Morinda lucida exhibited the best inhibitory activity on the two enzymes studied and the presence of phytochemicals like flavonoids, saponins, and tannins may have contributed greatly to the inhibitory activity of the plant extract.

Chemical composition, antimicrobial, and cytotoxicity studies on S. erianthum and S. macranthum essential oils.

CONTEXT: Solanum erianthum D. Don and Solanum macranthum Dunal (Solanaceae) are widely used in traditional medicine. The leaves act as an abortifacient and in particular to treat leucorrhoea, sores, and skin irritations. OBJECTIVE: This study was undertaken to characterize the volatile constituents of the leaf and fruit essential oils of S. erianthum and S. macranthum; their antimicrobial and in vitro cytotoxic bioassay against human breast and prostate tumor cells. METHODS: The volatile oils were obtained by hydrodistillation and analyzed for their constituents by gas chromatography-mass spectrometry (GC-MS). Minimum Inhibitory Concentrations (MIC) were determined using the microbroth dilution technique while the cytotoxic potentials were evaluated using the Cell Titre 96((R)) AQ(ueous) Non-Radioactive Cell Proliferation Assay method. RESULTS: Solanum erianthum essential oils were characterized by the abundance of α-terpinolene (17.8%), α-phellandrene (17.5%), p-cymene (15.7%) and ß-pinene (11.7%) in the leaves; α-humulene (23.1%), humulene epoxide II (20.0%), caryophyllene oxide (16.5%), methyl salicylate (11.8%) and ß-caryophyllene (10.9%) in the fruits. The leaf oil of S. macranthum consisted of (E)-phytol (29.0%), pentadecanal (28.1%) and pentadecane (7.7%) while the major fruit oil constituents were α-humulene (36.5%), ß-caryophyllene (17.8%), ethyl palmitate (9.4%), and methyl salicylate (8.2%). Solanum erianthum leaf volatile oil demonstrated potent inhibitory activity against Hs 578T and PC-3 human breast and prostate tumor cells respectively. In addition, the Solanum essential oils exhibited significant antimicrobial activity (19.5-625 µg/mL) on pathogens employed in the assay. CONCLUSION: The Solanum essential oils possess strong antimicrobial activity in addition to the potent cytotoxic potential of S. erianthum leaf oil against Hs 578T and PC-3 cells.

Anti-hyperglycemic Potential of Natural Products.

In order to evaluate the anti-hyperglycemic effect of natural compounds via the inhibition of alpha-glucosidase (AGH), the potential inhibitory effect of anthocyanins, caffeic acid analogs, and caffeoylquinic acid analogs have been reviewed. A new AGH assay system to mimic the membrane-bound AGH at the small intestine was proposed and evaluated.

Phytochemical and antimicrobial studies on Butyrospermum paradoxum.

The methanolic extracts of the leaves, stem bark, root bark, fruits and seeds kernels of Butyrospermum paradoxum have been evaluated for their phytochemical constituents, antibacterial and antifungal properties.

Antiulcerogenic effects of Tylophora conspicua in male rats.

Studies were undertaken on the effect of a crude (TC) and an alkaloid fraction (TA) of the leaf extracts of Tylophora conspicua on indomethacin-induced gastric ulceration and gastric acid secretion in male albino rats. Both the TC and TA produced a dose-dependent inhibition of gastric ulceration. At a dose level of 40 mg/kg TC and TA were more effective (TA being more potent) than propranolol in inhibiting gastric ulceration. The highest dose of the extracts used (80 mg/kg) completely inhibited gastric ulceration. Intravenous administration of the TC and TA significantly decreased acid output at low dose (20 mg/kg), medium dose (40 mg/kg) and high dose (80 mg/kg) from the peak basal of 0.54 +/- 0.02 mEq/L/min to 0. 49 +/- 0.02 mEq/L/min, 0.35 +/- 0.01 mEq/L/min and 0.21 +/- 0.02 Meq/L/min respectively. 80 mg/kg of TC and TA significantly reduced the histamine (1 mg/kg) induced gastric acid secretion. The results suggest that the antiulcer activity of Tylophora conspicua might be produced by gastric acid inhibition.