K.N. Chidambara Murthy

Study on Wound Healing Activity of Punica granatum Peel

The methanolic extract of dried pomegranate (Punica granatum) peels showed the presence of a high content of phenolic compounds (44.0%) along with other constituents. This extract was formulated as a 10% (wt/wt) water-soluble gel and was studied for its wound healing property against an excision wound on the skin of Wistar rats. The activity was compared with that of a commercial topical antibacterial applicant. The wound healing activity was assessed by measuring the percent contraction in skin and estimation of collagen content in terms of hydroxyproline content. Healed skin was also subjected to histopathological studies to examine the microscopic changes. The animals treated with 2.5% gel showed moderate healing (55.8% and 40.8% healing compared with negative and positive controls, respectively), whereas the group treated with 5.0% gel showed good healing (59.5% and 44.5% healing compared with negative and positive controls, respectively). The amount of hydroxyproline increased by twofold in the group treated with 5.0% gel. Histopathological studies also supported the wound healing on application of the gels. The group of rats that received 5.0% gel showed complete healing after 10 days, whereas in rats treated with 2.5% gel, healing was observed on day 12, in contrast to the positive control animals receiving the blank gel, which took 16-18 days for complete healing. The results of this study may be extended to different types of wounds so that the formulation could be exploited to develop it as a topical dermatological formulation. High-performance liquid chromatography analysis of the extract showed the presence of gallic acid and catechin as major components.

Antioxidant and antimicrobial activity of Cissus quadrangularis L.

Extracts of Cissus quadrangularis L. were tested for antioxidant activity by beta-carotene linoleic acid model and also by 1,1-diphenyl-2-picrylhydrazyl model. The ethyl acetate fraction of both fresh and dry stem extracts at a concentration of 100 ppm showed 64.8% antioxidant activity in the beta-carotene linoleic acid system and 61.6% in the 1,1-diphenyl-2-picrylhydrazyl system. This fraction showed the presence of sterols, vitamin C, and tannins as phytoconstituents. The antioxidant activity of methanol extract and aqueous extract were comparatively less significant than that of ethyl acetate extract, and n-hexane extract showed the least activity. The ethyl acetate extract and methanol extract of both fresh and dry stems further exhibited antimicrobial activity against Gram-positive bacteria, including Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Streptococcus species. The results of the study have implications in the use of C. quadrangularis as an antibacterial agent and more so as an antioxidant in several applications requiring these properties.

Differential inhibition of human colon cancer cells by structurally similar flavonoids of citrus

A number of studies in the recent years have evaluated the anti-proliferative activity of flavonoids. Although certain studies investigated the structure-activity based on the phenotypic assays, no study has correlated the flavonoids structure with the ability to alter gene/protein expression. Present study was focused to understand the structure-function relationship of citrus flavonoids in terms of their ability to alter the gene expression in the colon adenocarcinoma cells. Eight structurally related flavonoids found in citrus were evaluated for their ability to inhibit colon cancer (SW480) cells, as well as change the expression of apoptosis related genes/proteins. Apigenin and quercetagetin demonstrated most significant inhibition of cell proliferation with 63.6% and 45.7% inhibition of cell growth at 200μM after 48h of incubation, respectively. The cell death was also confirmed by images of fluorescently tagged cells. Furthermore, up-regulation of Bax/Bcl2 protein ratio as well as activation of Caspase3 at 200μM at 48h confirmed the induction of apoptosis by apigenin and quercetagetin. In addition, results suggest that the change in Bax/Bcl2 ratio by apigenin and quercetagetin seems to be due to their ability to alter the expression of bax and bcl2 transcription. Results of the currents study suggest that among the citrus flavonoids, double bond between C2 and C3 and hydroxyl group at C3, C6 are highly decisive for the proliferation inhibition and apoptosis induction ability. Taken together, these results demonstrate that among the major flavonoids of citrus, apigenin and quercetagetin have potent anti-cancer activity through inducing apoptosis in SW480 human colon cancer cells.

Nutraceutical Applications of Garlic and the Intervention of Biotechnology

Garlic (Allium sativum L.) is an important and widely cultivated plant with both culinary and medicinal uses stemming from its biological activities, which include antibiotic, anticancer, anti-thrombotic, and lipid-lowering cardiovascular effects. Though such medicinal use of garlic existed for centuries, there was little scientific support for its therapeutic and pharmacological properties. However, there has been a recent upsurge of research on garlic aiming to understand its exact mechanism of action in each case so that garlic and its products may have more judicious future applications. Since garlic is vegetatively propagated, its improvement for desired traits through conventional means is difficult. The intervention of biotechnological methods such as tissue culture and gene transfer protocols developed recently hold great promise for improving this crop. Due to new innovations in instrumentation and processing technologies coupled with more judicious experimental models, better products are foreseen in the market. The objective of this article was to review the recent developments made towards understanding the mechanism by which garlic imparts different therapeutic effects as well as to review what biotechnology can offer to improve this crop and its products.

Obacunone and obacunone glucoside inhibit human colon cancer (SW480) cells by the induction of apoptosis.

OBJECTIVES The study was aimed to purify obacunone and obacunone glucoside (OG) from seeds of Marsh White grapefruit and understand the mode of cytotoxicity of limonoids on colon cancer (SW480) cells. METHODOLOGY Both limonoids were purified using chromatographic techniques. The structures and purity of limonoids were confirmed by NMR and HPLC analysis, respectively. RESULTS Obacunone and OG inhibited SW480 cell proliferation with IC50 values of 97 and 109.7 μM respectively, at 24h. Sequence of events such as decreased ratio of bcl2/bax gene transcription, activation of caspase-3, fragmentation of DNA in cells treated with obacunone and OG demonstrated induction of apoptosis by limonoids. Additionally, higher induction of cytochrome-c in cytosol suggests the activation of intrinsic apoptosis by limonoids. Involvement of apoptosis was also confirmed through expression of bax, bcl2, pro-caspase-3 and caspase-9. Both the limonoids activated p21 and arrested cells at G1 and G2/M phase. Additive activity of proliferation inhibition and activation of caspase-3 by limonoids was observed when combined with camptothecin, demonstrating the induction of apoptosis. In conclusion, both limonoids induced apoptosis by activation of intrinsic apoptosis pathway and activation of p21 leading to arresting cells at G2/M phase of the cell cycle.

Effect of the Carotenoid-Producing Alga, Dunaliella bardawil, on CCl4-Induced Toxicity in Rats

Dunaliella bardawil is a carotenoid-producing alga that is being considered for use in nutraceuticals. To evaluate potential protective effects of consumption of this alga, rats were treated with two different doses of D. bardawil (2.5 and 5.0 g kg–1 body weight [bw]) as a biomass suspension daily for 14 days. Animals were tested against Carbon tetrachloride (CCl4; 2 ml kg–1)–induced liver toxicity as measured by various biochemical marker enzymes in liver and blood. All measurements were taken 6 h following the single dose of CCl4. The results of this study show that there was a slight, but statistically significant mean serum enzyme values, with D. bardawil treatment, compared to higher mean values in animals receiving CCl4 alone. Lipid peroxidation is measured by thiobarbituric acid–reactive substance (TBARS) activity was likewise slightly less elevated with algae treatment. The results also demonstrated protection against DNA strand breaks in hepatocytes, as measured by single cell gel electrophoresis. Liver histopathology was less severe with D. bardawil treatment, supporting the apparent protective action of 14-day treatment on hepatic oxidative injury.