COX-2 inhibitors from stem bark of Bauhinia rufescens Lam. (Fabaceae)

Chemical investigation of the stem bark of Bauhinia rufescens resulted in the isolation of a new cyanoglucoside and menisdaurin from methanol extract and oxepin from petroleum ether extract. The isolated compounds were tested for their anti-inflammatory potentials based on the cyclooxygenase-2 enzyme (COX-2) model. Cyanoglucoside exhibited the highest activity among the compounds with an inhibition activity of 49.34 % at 100 μM (IC50 0.46 μM) compared to the positive control, indomethacin (79.20 %, IC50 0.24 μM)

Determination of the absolute configuration of new piperidin-4-one derivative from pellacalyx saccardianus by NOESY spectroscopy

A new alkaloid, pellacalyxin was isolated from the leaves of Pellacalyx saccardianus of Rhizophoraceae family. Pellacalyxin was analyzed using nuclear Overhauser spectroscopy (NOESY) nuclear magnetic resonance (NMR) technique to determine the absolute configuration. The analysis of absolute configuration of pellacalyxin was supported by X-ray crystallography.1H-1H NOESY NMR spectroscopy exhibited that pellacalyxin possesses two chiral centers (3S) and (6R)

Chemical Constituents of Alpinia purpurata

The rhizomes of Alpinia purpurata collected in Universiti Teknologi Malaysia, Skudai contained an unstable labdane diterpene, labda-8 (17), 12-diene-15, 16dial and an alkaloid piperine. Their structures were established by spectroscopic methods. This is the first report on the isolation of a piperine alkaloid from an Alpinia species

Essential oil constituents of Alpinia mutica Roxb.

The oil of Alpinia mutica Roxb was produced by hydrodistillation from fresh rhizomes, collected from cultivated plants in Universiti Pertanian Malaysia. The oil was analyzed by GC/MS and 24 components were identified which constituted 87.5% of the oil. The major components of the oil were camphor (35.6%), 1,8-cineole (9.4%) and borneol (8.3%)

A Labdane Diterpene from Enicosanthum congregatum

A labdane diterpene was isolated from the air-dried leaves of Enicosanthum congregatum. The structure has been established as 8,I6-dihydroxy-ent-Iabd-13en- 15-oic lactone on the basis of spectroscopic data

Isolation, characterization and modification of zerumbone from zingiber zerumbet

Zingiber zerumbet Smith belongs to Zingiberaceae family. The most important part of this plant is its rhizomes which have been associated with variety of medicinal uses. Rhizome of the Zingiber Zerumbet Smith is pale yellow with pungent smell and used as traditional medicine in relieving stomach ache, as a diuretic, and when macerated in alcohols are regarded as a tonic and depurative. Hydrodistillation of the rhizome of Zingiber zerumbet yield essential oil with five major compounds which are zerumbone (79.79%), α-humulene (6.85%), camphene (1.04%), caryophyllene oxide (1.36%), and (1R,3E,7E,11R)-1,5,5,8-tetramethyl-12-oxabicyclo-9,1,0-dodeca-3,7-diene (3.24%). The soxhlet extraction method of the rhizome using n-hexane as solvent yielded pale yellow extract crude (8.45 g, 1.69%). Recrystallization of the crude yielded zerumbone as white crystal solid (0.191 g, 2.26%). The zerumbone undergo reactions with m-CPBA in dichloromethane to give zerumbone epoxide (152 mg, 89.91%). Both zerumbone and zerumbone epoxide were characterized using 1H and 13C NMR spectroscropy

Total phenolic, antioxidant, antimicrobial activities and toxicity study of Gynotroches axillaris Blume (Rhizophoraceae)

The antioxidant activity and the total phenolic content, as well as the influence of petroleum ether, chloroform and methanol extracts from the leaves of Gynotroches axillaris, on microorganisms were studied. The total phenolic contents were evaluated by using Folin-Ciocalteu reagent and the obtained values ranged from 70.0 to 620 mg GAE/g. The efficiency of antioxidation, which was identified through the scavenging of free radical DPPH, exhibited that the highest IC50 was in the methanolic extract (44.7 μg/mL) as compared to the standard ascorbic acid (25.83 μg/mL) and to standard BHT (17.2 μg/mL). In vitro antimicrobial activity of extracts was tested against Gram-negative bacteria, Gram-positive bacteria and fungi. Methanol extract showed activity in the range (225-900 μg/mL) with both types, while petroleum ether and chloroform extracts were only active with Bacillus subtilis. The three extracts strongly inhibited all fungi with activity 225-450 μg/mL. The toxicity test against brine shrimps indicated that all extracts were non-toxic with LC50 value more than 1000 μg/mL. The finding of this study supports the safety of these extracts to be used in medical treatments

Chemical compositions and antibacterial activity of the leaf and stem oils of Piper porphyrophyllum (Lindl). N.E. Br.

The essential oils obtained by hydrodistillation from the fresh leaf and stem of Piper porphyrophyllum N.E. Br. were analyzed by GC and GC/MS. Thirty four constituents were identi-fied in the leaf oil, while thirty eight constituents were identified in the stems oil. The most abundant components in the leaf oil included bicyclogermacrene (14.7 %), α-copaene (13.2 %) and β-phellandrene (9.5 %) while sabinene (15.5 %), bicyclogermacrene (12.3 %) and α-copaene (8.1 %) were the main constituents in the stem oil. The evaluation of antibacterial activity by using microdilution method revealed that both oils were moderately active against all the Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas putida and Escherichia coli) with minimum inhibitory concentration (MIC) values in the range 125-1000 μg/ml

Phytochemistry and antioxidant activity of garcinia prainiana

Phytochemical investigation of the leaves and stem bark of G. prainiana was carried out. The leaves and stem barks of G. prainiana collected from Kuantan, Pahang were extracted by soxhletextractorwith hexane, dichloromethane and methanol to get the crude exkacts. The crude extracts were purified by column chromatography io yield pure compounds which were characterized spectroscopically using lR, NMR (1D and 2D), UV and MS. Fractionation and purification of the hexane extract of leaves yielded triterpenes, squalene and friedelin. The methanol extract of leaves and stem barks afforded bioflavonoid characterized as morelloflavone and O-methyl fukugetin. Total phenolic content studies were carried out on the crude extracts by using Folin-Ciocalteau reagent. The methanol extract of leaves and stem barks showed the highest total phenolic content expressed as gallic acid and (t)-catechin equivalents. These extracts also showed the highest value of ascorbic acid and butylated hydroxytoluene (BHT) equivalents on forming the phosphomolybdenum complex in the total antioxidant assay. The antioxidant assay on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical showed that the methanolextract of stem barks had the highest free radical scavenging activity with lCso value 74.5trr9/ml while the isolated compound, morelloflavone revealed a strong free radical scavenging activity with lCsovalue 15.7p9/m

[1R-(1α,2α,4α,5β,6α,7α)]-4-Benzoyl­oxymethyl-5,6-dihy­droxy-3,8-dioxa­tricyclo­[5.1.0.02,4]octan-5-yl acetate (3-deacetyl­crotepoxide) from Kaempferia rotunda Val.

The title compound, C16H16O7, isolated from Kaempferia rotunda rhizomes, features a six-membered cyclo­hexane ring that adopts a twisted-boat conformation owing to the presence of two adjacent epoxide attachments that lock in four of the six axial positions. The CH3CO2– and HO– substituents occupy equatorial positions. However, the bond angles at the ring carbon connected to the C6H5CO2CH2– substituent deviate signifcantly from the idealized tetra­hedral angles as the carbon atom is part of an epoxide ring. In the crystal, the molecules are linked into chains by O—H⋯O hydrogen bonds