Gajanan J. Chintalwar

An immunologically active arabinogalactan from Tinospora cordifolia

An arabinogalactan of mean M(r) 2.2 x 10(6) has been isolated from the dried stems of Tinospora cordifolia and examined by methylation analysis, partial hydrolysis and carboxyl reduction. Purified polysaccharide showed polyclonal mitogenic activity against B-cells, their proliferation did not require macrophages.

Protective Activities of Some Phenolic 1,3-Diketones against Lipid Peroxidation: Possible Involvement of the 1,3-Diketone Moiety

The protective activities of four ginger‐derived phenolic 1,3‐diketones (1–4) and curcumin (5) against lipid peroxidation was studied by using different biologically relevant model systems and pulse radiolysis. The extraordinary activity of 5 vis‐à‐vis 1–4 against Fe2+‐mediated peroxidation may be attributed to the additional phenolic hydroxy group in the former, which lends it better iron‐chelating and radical‐scavenging properties. In iron‐independent peroxidation, however, the ginger constituent [6]‐dehydrogingerdione (1) showed activity comparable to that of 5; this indicates its higher affinity for the lipid peroxide radical (LOO.), due to its higher hydrophobicity. A very high rate constant for the reaction between 1 and Cl3COO., measured by pulse radiolysis, not only confirmed this, but also established the superior antioxidant efficacy of 1 in comparison to vitamins E and C. This was also evident from the results obtained from a liposomal peroxidation study with 1 and vitamin C. This study also established a synergistic effect of the latter on the antioxidant activity of 1. HPLC analysis of the products of the reaction between 1 and Cl3COO. revealed the formation of higher concentrations of ferulic acid (7), along with vanillin (6). The presence of ascorbate affected the generation of 7 more than it did that of 6. On this basis, a mechanism for the antioxidant action of 1 has been proposed, which suggests the contribution of the phenolic group as well as the active methylene group of the 1,3‐diketones.

Antioxidant properties of a Tinospora cordifolia polysaccharide against iron-mediated lipid damage and γ-ray induced protein damage

Abstract The antioxidant activity of an arabinogalactan polysaccharide (TSP) isolated from Tinospora cordifolia, an Indian medicinal plant, was studied. The polysaccharide showed good protection against iron-mediated lipid peroxidation of rat brain homogenate as revealed by the thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxide (LOOH) assays. TSP also provided significant protection to protein against γ-ray induced damage. The protective action can possibly be explained by its very high reactivity towards DPPH, superoxide radicals and the most damaging of radicals, the hydroxyl radical.

Isolation of ecdysterone from indian plants

Abstract Ecdysterone has been isolated from the following plants: Achyranthes aspera, Gomphrena celosioides, Trianthema portulacastrum and Sesuvium portulacastrum, the latter being one of the best sources for ecdysterone.

The metabolic fate of [35S]-diallyl disulphide in mice

Diallyl disulphide (DADS) is a major constituent of garlic oil. Uptake of [35S]-labelled diallyl disulphide by mouse liver is highest at 90 min after treatment. 2h after treatment with [35S]-DADS, 70% of the radioactivity is present in the liver cytosol of which 80% is metabolized to sulphate.

Molecular events in the activation of B cells and macrophages by a non-microbial TLR4 agonist, G1-4A from Tinospora cordifolia

G1-4A, a polysaccharide from an Indian medicinal plant Tinospora cordifolia, was recently shown to protect mice against septic shock by modulating the proinflammatory cytokines. G1-4A also activated B cells polyclonally. The present report describes in detail the molecular events associated with G1-4A-induced immunomodulation in vitro and in vivo. G1-4A treatment led to an increase in the CD69 expression in lymphocytes. G1-4A-induced proliferation of B cells was completely inhibited by PI3K inhibitor Ly294002, mTOR inhibitor rapamycin and NF-kappaB inhibitor plumbagin. Akt, ERK and JNK were activated by G1-4A which finally resulted in the activation of IKK, degradation of IkappaB-alpha and translocation of NF-kappaB to the nucleus. Administration of G1-4A to mice led to splenomegaly and an increase in the numbers of T cells, B cells and macrophages. This increase in spleen cellularity was due to in vivo proliferation of lymphocytes and upregulation of anti-apoptotic genes. Anti-TLR4-MD2 complex antibody inhibited G1-4A-induced B cell proliferation and degradation of IkappaB-alpha suggesting that TLR-4 was a receptor for G1-4A on B cells. Activation of RAW 264.7 macrophages by G1-4A was found to be dependent on ERK and NF-kappaB-mediated signals. The phagocytosis index in peritoneal exudate cells (PEC) isolated from G1-4A treated mice was significantly higher as compared to that in PEC from control mice. G1-4A administration also increased the number of CD11b(+) cells in the PEC without an increase in the total number of PEC. Thus the present understanding of the molecular mechanism of action of G1-4A, a novel non-microbial TLR4 agonist, will pave the way for its application as an immunomodulator and adjuvant.

Antioxidant and radioprotective properties of an Ocimum sanctum polysaccharide

Abstract The antioxidant activity of two polysaccharides isolated from the Indian medicinal plants, Ocimum sanctum and Tinospora malabarica, was studied. Only the O. sanctum polysaccharide (OSP) showed significant activity. OSP could prevent oxidative damage to liposomal lipids and plasmid DNA induced by various oxidants such as iron, AAPH and γ-radiation, besides scavenging important ROS such as the superoxide radical and hydrogen peroxide and inhibiting xanthine oxidase. In addition, OSP could prevent γ-radiation-mediated cell deaths in mouse splenocytes.

Environmental persistence of diallyl disulfide, an insecticidal principle of garlic and its metabolism in mosquito, Culex pipiens quinquifasciatus Say

Abstract Diallyl disulfide (DADS), a major insecticidal principle of garlic, Allium sativum L, has low environmental persistence; there is an exponential loss of [35S] DADS from the treated water with respect to time. Compared to larvae, pupae of Culex pipiens quinquifasciatus Say, exhibit higher tolerance to this pesticide. Both, larvae and pupae metabolise [35S] DADS to inorganic [35S] sulfate.

Structural confirmation of decussatin, a Swertia decussata xanthone

Reinvestigation of the plant, Swertia decussata resulted in the isolation of four antioxidant xanthones, which were characterized as 1-hydroxy-3,7,8-trimethoxy, 1,8-dihydroxy-3,7-dimethoxy, 1,7-dihydroxy-3,8-dimethoxy and 1,7,8-trihydroxy-3-methoxyxanthones. The structural ambiguity of the first compound was settled by ASIS-NMR and 2D NOESY spectroscopy.

Biosynthesis of bakuchiol, a meroterpene from Psoralea corylifolia

Significant incorporations of labelled leucine, valine and isovaleric acid into the meroterpene, bakuchiol (1) isolated from the medicinal plant, Psoralea corylifolia have been observed. Degradation experiments show that labels from these substrates find their way into both phenylpropane derived as well as terpenic part of 1 thereby indicating that none of the known pathways is operative in the case of 1. It is suggested that these substrates are metabolised to CO2 which is then incorporated into 1.