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The rhizomes ofAstilbe rivularis, commonly known as ‘Thulo Okhati’ are widely used in Nepal as tonic for uterine and menstrual disorders. In our preliminary study, the 70% MeOH extract of the rhizomes showed potent antioxidant activity. Hence, present study was aimed for the isolation of potent antioxidant constituents. Bergenin (1), 11-O-galloylbergenin (2), (+)-catechin (3), (−)-catechin (4), (−)-afzelechin (5), (−)-epiafzelechin (6) and 2-(β-D-glucopyranosyloxy)-4-hydroxylbenzenacetonitrile (7) were isolated from the rhizomes. Structures of these compounds were elucidated on the basis of spectroscopic methods. All these isolated compounds were evaluated for theirin vitroantioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. 11-O-Galloylbergenin (2), (+)-catechin (3), (−)-catechin (4), (−)-afzelechin (5) and (−)-epiafzelechin (6) showed potent antioxidant activity. [ABSTRACT FROM PUBLISHER] more...

Despite the development of a range of anti-cancer agents, cancer diagnoses are still increasing in number, remaining a leading cause of death. Anticancer drug treatment is particularly important for leukemia. We screened Turkish plants and found the unique antileukemic activity of twig components in Turkish Caucasian beech, selectively inducing apoptosis in leukemia cells. This effect is unique among some kinds of beeches, presumably related to oxidative stress. This study would lead to effective use of discarded material, i.e., twig of beech, and a new anti-leukemic drug based on large tree. [ABSTRACT FROM AUTHOR] more...

The introduction of combined anti-retroviral therapy (cART) in 1996, along with a continual breakthrough in anti-human immunodeficiency virus-1 (HIV-1) drugs, has improved the life expectancies of HIV-1-infected individuals. However, the incidence of drug-resistant viruses between individuals undergoing cART and treatment-naïve individuals is a common challenge. Therefore, there is a requirement to explore potential drug targets by considering various stages of the viral life cycle. For instance, the late stage, or viral release stage, remains uninvestigated extensively in antiviral drug discovery. In this study, we prepared a natural plant library and selected candidate plant extracts that inhibited HIV-1 release based on our laboratory-established screening system. The plant extracts from Epilobium hirsutum L. and Chamerion angustifolium (L.) Holub, belonging to the family Onagraceae, decreased HIV-1 release and accelerated the apoptosis in HIV-1-infected T cells but not uninfected T cells. A flavonol glycoside quercetin with oenothein B in Onagraceae reduced HIV-1 release in HIV-1-infected T cells. Moreover, extracts from Chamerion angustifolium (L.) Holub and Senna alexandrina Mill. inhibited the infectivity of progeny viruses. Together, these results suggest that C. angustifolium (L.) Holub contains quercetin with oenothein B that synergistically blocks viral replication and kills infected cells via an apoptotic pathway. Consequently, the plant extracts from the plant library of Turkey might be suitable candidates for developing novel anti-retroviral drugs that target the late phase of the HIV-1 life cycle. more...

Three new diterpenes, stellejasmins A ( 1 ) and B ( 2 ) and 12- O -benzoylphorbol-13-heptanoate ( 3 ), were isolated from the roots of Stellera chamaejasme L. The structures of 1 - 3 were elucidated by extensive NMR and mass spectroscopic analyses. Compounds 1 and 2 are the first derivatives containing a hydroxy group at C-2 in the family of daphnane and tigliane diterpenes. The presence of a chlorine atom in 1 is unique in the plant metabolite. Compound 3 has an odd-number acyl group, which is biosynthetically notable. Human immunodeficiency virus (HIV) LTR-driven transcription activity was tested with 1 - 3 and 17 known diterpenes isolated from S. chamaejasme L. and Wikstroemia retusa A.Gray. Among these, gnidimacrin ( 4 ), stelleralide A ( 5 ), and wikstroelide A ( 20 ) were highly potent, with EC 50 values of 0.14, 0.33, and 0.39 nM, respectively. The structure-activity relationship (SAR) was investigated using 20 natural and eight synthetic diterpenes. This is the first SAR study on natural daphnane and tigliane diterpenes. more...

Background : Blepharis linariifolia Pers. (Family: Acanthaceae) is used in traditional medicines as a general tonic and for the treatment of various health problems in Sudan. The main aim of this study was to isolate and identify the major chemical constituents from the aerial parts of B. linariifolia and evaluate their bioactivities. Methods : The dried aerial parts of the plant were extracted successively with 100% acetone and 50% acetone, and thereafter the combined extract was subjected to repeated column chromatography to isolate the main components. Free radical scavenging activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical method, and in vitro enzyme inhibitory activities against α-glucosidase, pancreatic lipase, and mushroom tyrosinase were evaluated. Results : From the detailed chemical analysis, verbascoside ( 1 ), vanillic acid ( 2 ), apigenin ( 3 ), and 6''- O - p -coumaroylprunin ( 4 ), were isolated and their structures were identified on the basis of their nuclear magnetic resonance (NMR) spectral data. Among the isolated compounds, verbascoside ( 1 ) showed the most potent free radical scavenging activity (IC 50 = 22.03 ± 0.04 μM). Apigenin ( 3 ) and 6''- O - p -coumaroylprunin ( 4 ) showed promising inhibitory activities against all tested enzymes. Apigenin ( 3 ) showed the most potent inhibitory activity against α-glucosidase and tyrosinase (IC 50 = 34.73 ± 1.78 μM and 23.14 ± 1.83 μM, respectively), whereas 6''- O - p -coumaroylprunin ( 4 ) showed potent inhibition for lipase (IC 50 = 2.25 ± 0.17 μM). Conclusions : Four phenolic compounds were isolated and identified from B. linariifolia acetone extract, which are reported for the first time from this plant. All compounds showed good DPPH free radical scavenging activities, with verbascoside (1) being the most potent. Apigenin (3) was the most active as α-glucosidase and mushroom tyrosinase inhibitor, while 6''- O - p -coumaroylprunin ( 4 ) showed potent inhibitory activity for pancreatic lipase., Competing Interests: The authors declare no conflict of interest. more...