Nilufar Nahar

Variation of carbohydrate composition of two forms of fruit from jack tree (Artocarpus heterophyllus L.) with maturity and climatic conditions

Abstract Soft and firm varieties of jackfruit of three stages of maturity (7–8, 10–12, and 14–16 weeks), harvested from the central, western and eastern parts of Bangladesh, were analysed. The dry matter content of perianth and seed of the soft and firm varieties increased from 10.0 to 32.0% and 19.0 to 52.0%, respectively, while the ash content decreased from 5.7 to 2.0% and 4.9 to 1.5%, respectively, on a dry matter basis. The free sugars of jackfruit samples increased with maturity from 1.5 to 10.5% and 1.4 to 5.2% of their dry matter for the soft and firm varieties, respectively. In all cases varying proportions of glucose, fructose and sucrose were the major sugar constituents. The starch content of the perianth samples increased from 7.8 to 47.0% and from 9.0 to 50.5%, on a dry matter basis for the soft and firm varieties, respectively, whereas, that for seed increased up to 65.0 and 59.0%, respectively. Microscopic examination of the samples showed the perianth to contain thin-walled cells packed with starch granules, some organized into distinct clusters. From both the chemical and histological studies, it appeared that the starch content of both perianth and seed of soft and firm varieties of jackfruit samples gradually increased with the increase of maturity. The total dietary fibre varied from 42.0 to 55.0% in the perianth. However, that of seed changed very little. The results show that the starch and total dietary fibre contents of jackfruit are higher than those of other fruits and vegetables of Bangladesh. ©

An unusual (4-O-methyl-d-glucurono)-d-xylan isolated from the mucilage of seeds of the quince tree (Cydonia oblonga)

Abstract The major water-soluble polysaccharide in the mucilage of the seeds of the quince tree, Cydonia oblonga , is a partially O -acetylated(4- O -methyl- d -glucurono)- d -xylan having an exceptionally high proportion of glycuronic acid residues. The 4- O -methyl-α- d -glucopyranosyluronic and α- d -glucopyranosyluronic acid groups are linked to positions 2 of a (1 → 4)-β- d -xylan that is somewhat branched through the 2-positions. The O -acetyl groups are linked to the β- d -xylopyranosyl residues. The molar proportions of d -Xyl, 4- O -Me- d -GlcA, d -GlcA, and O -Ac are ∼ 2:0.8:0.2:1.

Hypoglycaemic and antioxidant activities of Ficus racemosa Linn. fruits

The effects of Ficus racemosa Linn. fruit extract and fraction on fasting serum glucose levels of normal, type 1 and type 2 diabetic model rats are presented. The aqueous 80% EtOH extract and its water soluble fraction of F. racemosa fruit did not show any serum glucose lowering effect on non-diabetic and type 2 diabetic rats at the fasting condition, whereas the extract showed significant hypoglycaemic effect on the type 1 diabetic model rats. Both the extract and fraction were consistently active in both non-diabetic and types 1 and 2 diabetic model rats when fed simultaneously with glucose load. On the contrary, they were ineffective in lowering blood glucose levels when fed 30 min prior to glucose load. The 1-BuOH soluble part of the ethanol extract exhibited significant antioxidant activity in DPPH free radical scavenging assay. 3-O-(E)-Caffeoyl quinate (1) was isolated for the first time from this plant, which also showed significant antioxidant activity.

Free radical scavenging phenylethanoid glycosides from Leucas indica Linn.

A new phenylethanoid glycoside, 2-(3,4-dihydroxyphenyl)-ethyl-O-α-L-rhamnopyranosyl-(1 → 3)-O-α-L-rhamnopyranosyl-(1 → 6)-4-O-E-feruloyl-β-D-glucopyranoside (3-O-methyl poliu-moside, 1) along with five known phenylethanoid glycosides (2–6) were isolated from the aerial parts of Leucas indica Linn. The structure of compound 1 has been elucidated on the basis of spectral data. Compounds 1–6 exhibited significant antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay method. These compounds were also found to be moderate inhibitors of xanthine oxidase (XO) enzyme.

Phosphodiesterase-I inhibitor quinovic acid glycosides from Bridelia ndellensis.

Quinovic acid-3-O-α-l-rhamnopyranoside (1), quinovic acid-3-O-β-d-fucopyranoside (2), quinovic acid-3-O-β-d-glucopyranosyl (1 → 4)-β-d-fucopyranoside (3), methyl gallate (4) and ethyl gallate (5) were isolated from the ethyl acetate extract of Bridelia ndellensis barks by fractionation. Compounds 1–3 showed significant inhibitory activity against snake venom phosphodiesterase-I.

Topical antiinflammatory activity of two pimarane diterpenes from Kaempferia pulchra

Two diterpenes, 2α‐acetoxysandraracopimaradien‐1α‐ol (1) and sandaracopimaradien‐1α,2α‐diol (2) isolated from Kaempferia pulchra Ridl. (Zingiberaceae), have been assayed for topical antiinflammatory activity in the model of 12‐O‐tetradecanoylphorbol‐13‐acetate‐induced ear oedema in rats. Both substances were found active and the ID50‐values were estimated to 330 and 50 μg/ear, respectively. The ID50‐value of the reference drug diclofenac was calculated to 90 μg/ear

Determination of alachlor residues in pepper and pepper leaf using gas chromatography and confirmed via mass spectrometry with matrix protection

Alachlor residues were determined in pepper and pepper leaf, after 49 days of manufacturer-recommended single- and double-dose application to the soil and plant. The samples were extracted with acetonitrile, partitioned with n-hexane, and purified through solid-phase extraction, and finally detected with a gas chromatography-microelectron capture detector. The linearity of the analytical response across the studied range of concentrations (0.05-4.0 µg/mL) was excellent, obtaining coefficients of determination (r(2) ) of 0.999. Recovery studies were carried out on spiked pepper and pepper leaf samples, at two concentrations levels (0.2 and 1.0 mg/kg), with three replicates performed at each level. Mean recoveries of 73.1-109.0% with relative standard deviations of 1.3-2.3% were obtained. The method was successfully applied to field samples, and alachlor residue was found in pepper (0.02 mg/kg) and pepper leaf (0.03 mg/kg), at levels lower than the maximum residue limits (0.2 mg/kg) set by the Korea Food and Drug Administration. The field-detected residues were further confirmed with gas chromatography-mass spectrometry with the help of pepper leaf matrix protection.

Analysis of free sugar and dietary fibre of some vegetables of Bangladesh

Abstract Free sugar and dietary fibre (DF) contents and compositions of the edible parts of seven vegetables of Bangladesh were determined. Total free sugars in the fresh vegetables varied from 0.2 to 1.8% whereas dietary fibre ranged from 3.4 to 6.1%. Among the seven vegetables, elongated bean had the best combination of low free sugar and high dietary fibre. Glucose was the main constituent of the total polysaccharide of the vegetables but galactose was the major component of the soluble DF.

Novel flavonoid glycosides from the bulbs of Urginea indica Kunth.

Three novel flavonoid glycosides, 5,6-dimethyoxy-3′,4′′-dioxymethylene-7-O-(6′′-β-D-glucopyranosyl-β-D-glucopyranosyl) flavanone (1), 5,4′-dihydroxy-3-O-α-L-rhamnopyranosyl-6-C-glucopyranosyl-7-O-(6′′-para-coumaroyl-β-D-glucopyranosyl) flavone (2) and 5,4′-dihydroxy-3-O-(2′′′′′-β-glucopyranosyl-α-L-rhamnopyranosyl)-6-C-glucopyranosyl-7-O-(6′′-para-coumaroyl-β-D-glucopyranosyl) flavone (3) were isolated from the 1-butanol soluble fraction of the bulbs of the plant Urginea indica (Indian squill). The structures of the compounds were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, NOESY, HSQC and HMBC) and mass spectra.

An endophytic Basidiomycete, Grammothele lineata, isolated from Corchorus olitorius, produces paclitaxel that shows cytotoxicity

Grammothele lineata, an endophyte isolated in our laboratory from jute (Corchorus olitorius acc. 2015) was found to be a substantial paclitaxel producer. Taxol and its related compounds, produced by this endophyte were extracted by growing the fungus in simple nutrient media (potato dextrose broth, PDB). Taxol was identified and characterized by different analytical techniques (TLC, HPLC, FTIR, LC-ESI-MS/MS) following its extraction by ethyl acetate. In PDB media, this fungus was found to produce 382.2 μgL-1 of taxol which is about 7.6 x103 fold higher than the first reported endophytic fungi, Taxomyces andreanae. The extracted taxol exhibited cytotoxic activity in an in vitro culture of HeLa cancer cell line. The fungal extract also exhibited antifungal and antibacterial activities against different pathogenic strains. This is the first report of a jute endophytic fungus harboring the capacity to produce taxol and also the first reported taxol producing species that belongs to the Basidiomycota phylum, so far unknown to be a taxol producer. These findings suggest that the fungal endophyte, Grammothele lineata can be an excellent source of taxol and can also serve as a potential species for chemical and genetic engineering to enhance further the production of taxol.