Phytochemical and Biological Investigation of an Indigenous Plant of Bangladesh, Gynura procumbens (Lour.) Merr.: Drug Discovery from Nature.

Gynura procumbens (Lour.) Merr. (Family: Asteraceae) is a tropical Asian medicinal plant found in Thailand, China, Malaysia, Indonesia, and Vietnam. It has long been utilized to treat a variety of health concerns in numerous countries around the world, such as renal discomfort, constipation, diabetes mellitus, rheumatism, and hypertension. The chemical investigation resulted in the isolation and characterization of six compounds from the methanol (MeOH) extract of the leaves of Gynura procumbens, which were identified as phytol (1), lupeol (2), stigmasterol (3), friedelanol acetate (4), ß-amyrin (5), and a mixture of stigmasterol and ß-sitosterol (6). In-depth investigations of the high-resolution 1H NMR and 13C NMR spectroscopic data from the isolated compounds, along with comparisons to previously published data, were used to clarify their structures. Among these, the occurrence of Compounds 1 and 4 in this plant are reported for the first time. The crude methanolic extract (CME) and its different partitionates, i.e., petroleum ether (PESF), chloroform (CSF), ethyl acetate (EASF), and aqueous (AQSF) soluble fractions, were subjected to antioxidant, cytotoxic, thrombolytic, and anti-diabetic activities. In a DPPH free radical scavenging assay, EASF showed the maximum activity, with an IC50 value of 10.78 µg/mL. On the other hand, CSF displayed the highest cytotoxic effect with an LC50 value of 1.94 µg/mL compared to 0.464 µg/mL for vincristine sulphate. In a thrombolytic assay, the crude methanolic extract exhibited the highest activity (63.77%) compared to standard streptokinase (70.78%). During the assay for anti-diabetic activity, the PESF showed 70.37% of glucose-lowering activity, where standard glibenclamide showed 63.24% of glucose-reducing activity.

Indole alkaloids from the leaves of Ravenia spectabilis engl. with activity against pancreatic cancer cell line.

Two previously undescribed indole alkaloids, 3-prenyl-5(3-keto-but-1-enyl) indole and 3-prenyl-indole-5-carbaldehyde, the structurally-related 3,5-diprenyl indole and four known alkaloids were isolated from the leaves of Ravenia spectabilis Engl. Structures were elucidated based on nuclear magnetic resonance (1D and 2D NMR) spectroscopic and mass spectrometric analysis. The previously undescribed compounds isolated were subsequently screened against the HeLa (human cervical cancer), MIA PaCa-2 (human pancreatic adenocarcinoma) and A549 (lung cancer) cell lines. Among the isolated compounds, 3,5-diprenyl indole was the most cytotoxic across all three cell lines (MIA PaCa-2 IC50 = 9.5 ± 2.2 µM). Molecular modelling studies suggested DNA intercalation as the mode of action of these compounds.

Synthesis of modified siRNA bearing C-5 polyamine-substituted pyrimidine nucleoside in their 3'-overhang regions and its RNAi activity.

Short interfering RNA (siRNA) induces specific gene silencing by the RNA interference (RNAi) pathway. Nucleosides in the 3'-overhang regions of siRNAs were replaced with 5-bis(aminoethyl)aminoethylcarbamoylmethyl-2'-deoxyuridine or thymidine. siRNA bearing modified nucleoside was more active in silencing the gene expression of hepatocyte nuclear factor 4α (HNF4α) compared with siRNA bearing thymidine.

Sialyllactose-binding modified DNA aptamer bearing additional functionality by SELEX.

We produced a novel cationic-charged modified DNA aptamer for sialyllactose that is a ubiquitous component of the cell surface responsible for the infection of several viruses by using the magnetic-particle-based SELEX method. After 13 rounds of selection we selected 22 clones as sialyllactose-binding DNA aptamers composed of several modified thymidines. The DNA aptamers could form a three-way junction structure that likely forms a binding site for siallyllactose. The three-way junction structure contains several modified thymidines bearing a positively-charged amino group at the C5 position, which could enhance the binding ability for silalyllactose which has a negatively-charged carboxyl group. The dissociation constant of the aptamer that showed the strongest sialyllactose-binding ability among the clones of the aptamers was 4.9 microM.