Isolation Of Bioactive Compounds Research Articles

Search for New Lead Compounds from Higher Plants

Higher plants represent a rich source of new molecules with pharmacological properties, which are lead compounds for the development of new drugs. During the last decades, the renewed interest in investigating natural products has led to the advent of several important drugs, such as the anticancer substances vinblastine, vincristine and taxol, or the antimalarial agent artemisinin. Success in natural products reasearch is conditioned by a careful plant selection, based on various criteria such as chemotaxonomic data, information from traditional medicine, field observations or even random collection. One main strategy in the isolation of new leads consists of the so-called bioactivity-guided isolation, in which pharmacological or biological assays are used to target the isolation of bioactive compounds. One major drawback of this strategy is the frequent isolation of known metabolites. Therefore, hyphenated techniques (LC-UV/DAD, LC-MS, LC-NMR) have been developed, in order to detect as early as possible potential original structures. These compounds can then be tested in various bioassays. Using a combination of hyphenated techniques and bioactivity-guided isolation procedures, a series of new diterpenoic antifungal quinones have been isolated from the African tree, Bobgunnia madagascariensis (Leguminosae) and recently patented for their strong activity and for their potential use in the treatment of systemic mycoses.

Bioactive Properties of Wild Blueberry Fruits

ABSTRACT:Bioactive extracts from wild blueberries were isolated, fractionated, and analyzed. Antioxidant activity, cardioprotective capacity, and ability to inhibit the initiation stage of chemically‐induced carcinogenesis were evaluated. Many fractions had antioxidant activity, especially those rich in anthocyanins and proanthocyanidins. The ease of isolation of bioactive compounds and the ability to obtain accurate bioassays depended strongly on the source material used. Extracts from spray‐dried formulations containing magnesium citrate and tri‐calcium phosphate provided easier materials for bioactivity assessment and demonstrated antioxidant, cancer preventive and cardioprotective activity. Extracts with potent antioxidant activity degraded readily, underscoring the need for rapid alternative fractionation tactics and rigorously controlled storage conditions.

An antitumor promoter from Moringa oleifera Lam.

In the course of studies on the isolation of bioactive compounds from Philippine plants, the seeds of Moringa oleifera Lam. were examined and from the ethanol extract were isolated the new O-ethyl-4-(α- l-rhamnosyloxy)benzyl carbamate ( 1) together with seven known compounds, 4(α- l-rhamnosyloxy)-benzyl isothiocyanate ( 2), niazimicin ( 3), niazirin ( 4), β-sitosterol ( 5), glycerol-1-(9-octadecanoate) ( 6), 3- O-(6′- O-oleoyl-β- d-glucopyranosyl)-β-sitosterol ( 7), and β-sitosterol-3- O-β- d-glucopyranoside ( 8). Four of the isolates ( 2, 3, 7, and 8), which were obtained in relatively good yields, were tested for their potential antitumor promoting activity using an in vitro assay which tested their inhibitory effects on Epstein–Barr virus-early antigen (EBV-EA) activation in Raji cells induced by the tumor promoter, 12- O-tetradecanoyl-phorbol-13-acetate (TPA). All the tested compounds showed inhibitory activity against EBV-EA activation, with compounds 2, 3 and 8 having shown very significant activities. Based on the in vitro results, niazimicin ( 3) was further subjected to in vivo test and found to have potent antitumor promoting activity in the two-stage carcinogenesis in mouse skin using 7,12-dimethylbenz( a)anthracene (DMBA) as initiator and TPA as tumor promoter. From these results, niazimicin ( 3) is proposed to be a potent chemo-preventive agent in chemical carcinogenesis.

Isolation of bioactive compounds in cyanobacteria from Chinese fresh water. 1. Trypsin inhibitor

Isolation of bioactive compounds in cyanobacteria from Chinese fresh water. 1. Trypsin inhibitor

Isolation of bioactive compounds in cyanobacteria from Chinese fresh water. 1. Trypsin inhibitor

SUMMARYA trypsin inhibitor, oscillapeptin d (1), was isolated from Oscillatoria agardhii, the strain isolated from wa‐terbloom samples of Dianchi Lake in Yunnan province in China. The structure was elucidated to be 1 by chemical degradation and 2‐D nuclear magnetic resonance (NMR) analyses. The inhibitor was a 3‐amino‐6‐hy‐droxy‐2‐piperidone (Ahp)‐containing cyclic depsipep‐tide.

Isolation of bioactive compounds from Helix aspersa nerve tissue and the effect of pqpplpryamide on heart, esophagus and central neurons of H. aspersa and rectum of Anodonta woodiana

1. 1. Both acetone and methanol extraction was used to isolate bioactive compounds from 1000 Helix aspersa brains. 2. 2. Seven compounds were isolated of which four were identified as follows: Ha-1, 5-hydroxytryptamine; Ha-3, GSPYFVamide; Ha-4, pQPPLPRYamide; Ha-5, SGYLAFPRMamide. There was insufficient material to identify Ha-2, Ha-6 and Ha-7. 3. 3. Ha-4, pQPPLPRYamide, was found to excite the heart of H. aspersa, relax the esophagus and both excite (mainly) and inhibit central neurons. In addition, this peptide contracted the rectum of Anodonta woodiana. 4. 4. It is concluded that pQPPLPRYamide is an example of a new molluscan peptide family, designated as PRYamide.