Records of Natural Products Articles

Objective of the present work was to evaluate ethanolic extract of Leucas ciliataleaves for possible antioxidant and hepatoprotective potential. Antioxidant activity of the extract was evaluated by using Diphenyl picryl hydrazyl (DPPH) radical scavenging, Nitric oxide (NO) radical scavenging, Iron chelation and Reducing power methods. Hepatoprotective activity of the extract was evaluated by carbon tetrachloride (CCl4) induced liver damage model in rats. The extract demonstrated a significant dose dependent antioxidant activity comparable with ascorbic acid. In hepatoprotective activity study, CCl4 significantly increased the levels of serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), alkaline phosphatase (ALP) and total bilirubin. Pretreatment of the rats with ethanolic extract of L. ciliata(100, 200 and 400mg/kg po) inhibited the increase in serum levels of SGPT, SGOT, ALP and total bilirubin and the inhibition was comparable with silymarin (100mg/kg po). The present study revealed that L. ciliataleaves have significant radical scavenging and hepatoprotective activity.

 Ribes biebersteinii Berl. (Grossulariaceae), commonly known as ‘reddish-black berry’, is an Iranian medicinal plant found mainly in the region of the Arasbaran forests in Iran. Reversed-phase preparative HPLC analyses of the methanol extract of the leaves of this plant afforded four flavonol glycosides, e.g. quercetin 3-O-sophoroside (1), quercetin 3-O-sambubioside (2), kaempferol 3-O-sophoroside (3) and kaempferol 3,5-di-O-b-D-glucopyranoside (4). The free-radical-scavenging properties of the n-hexane, DCM and MeOH extracts, as well as the isolated compounds 1-4 were evaluated by the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay.

 The chemical composition and cytotoxic activity of the essential oils extracted from leaves of Croton matourensis and flowers and leaves of Croton micans were investigated. GC-FID and GC-MS analysis revealed that forty six compounds comprised 95.5 % of C. matourensis essential oil, with the main components being fenchyl acetate (19.5%), methyleugenol (14.2%), isoelemicine (11.3%), elemicine (7.6%), spathulenol (6.9%) and valencene (5.8%). In the analysis of C. micans oils, 63 compounds that comprised 98.9% were identified from the flower oil, the principal being fenchyl acetate (41.6%), α-caryophyllene (12.6%), β-cubebene (5.0%), β-caryophyllene (5.5%), α-cubebene (5.3%), β-elemene (4.7%) and valencene (4.6%). The oil from leaves gave fenchyl acetate (25.3%) α-caryophyllene (20.7%), α-selinene (12.8%) and β-bourbene (9.3%) as major constituents. The cytoxicity of these oils was screened by the MTT method against three human tumour cell lines and primary culture of human dermis fibroblasts (normal control cells). The results indicate that the oils have a moderate cytotoxicity against LoVo (colon carcinoma), X-17 (colon carcinoma), HeLa (cervical cancer), and control cells.

The volatile constituents of three most common aromatic exotic weeds viz. Lantana camara L., Eupatorium adenophorum Spreng and Ageratum conyzoides L. of the Uttarakhand, India were analyzed by GC and GC-MS. The essential oil of Lantana camara L. was dominated by sesquiterpenoids (70.8%) represented by sesquiterpene hydrocarbons (68.7%) with germacrene D (27.9%), germacrene B (16.3%), b-caryophyllene (9.6%), b-selinene (6.2%), α-humulene (5.8%) as major constituents. Other constituents in significant amount were sabinene (5.6%) and 1,8-cineole (4.8%). Amorphenes viz. amorph-4-en-7-ol (9.6%), 3-acetoxyamorpha-4,7(11)-dien-8-one (7.8%) and amorph-4,7(11)-dien-8-one (5.7%) were identified as the marker constituents of Eupatorium adenophorum Spreng along with p-cymene (16.6%), bornyl acetate (15.6%) and camphene (8.9%). On the contrary, the essential oil of Ageratum conyzoides L. was characterized by the presence of high percentages of ageratochromene (precocene II, 42.5%), β-caryophyllene (20.7%), demethoxyageratochromene (precocene I, 16.7%), a-humulene (6.6%) and p-cymene (3.3%).

A conformational analysis of the cembrene diterpenoids cembrene, cembrene A, (3Z)-cembrene A, isocembrene, casbene, and incensole, has been carried out using density functional theory at the B3LYP/6-31G* level of theory.  A molecular docking analysis of these cembrenoids with tubulin has also been performed in order to assess the potential of tubulin binding of these cytotoxic agents.  The macrocyclic cembrenoids are conformationally mobile and numerous low-energy conformations were found.  Molecular docking reveals that the cembrenoids dock into the colchicine binding site of tubulin with comparable docking energies to colchicine.

Three lipocyclopeptides, aspartocins A (1), B (2), and C (3), were obtained   from the aspartocin complex by reversed-phase HPLC separation. Their structures were elucidated by spectroscopic studies coupled with the previously published chemical degradation results. All three compounds, 1, 2, and 3, share the same cyclic decapeptide core of cyclo(Dab2-Pip3-MeAsp4-Asp5-Gly6-Asp7-Gly8-Dab9-Val10-Pro11-). They differ only in the side chain moiety corresponding to Asp1-isotetradecenoic acid, Asp1-anteisotetradecenoic acid, and Asp1-isotridecenoic acid for aspartocins A, B, and C, respectively. The cyclic substructure of aspartocins contains two D-amino acid residues, and the geometry of the peptide linkages appears to be all trans including the two tertiary amide bonds. The result is consistent with the hypothesis that a normal peptide to be cyclic requires D-configured residues or cis amide bond(s) incorporated.