A. Saha

Bio: A. Saha is an academic researcher from University of Calcutta. The author has contributed to research in topics: Curcumin & Genotoxicity. The author has an hindex of 2, co-authored 2 publications receiving 70 citations.

Biological Properties of Curcumin-Cellular and Molecular Mechanisms of Action

Abstract: Curcuminoids, a group of phenolic compounds isolated from the roots of Curcuma longa (Zingiberaceae), exhibit a variety of beneficial effects on health and on events that help in preventing certain diseases. A vast majority of these studies were carried out with curcumin (diferuloyl methane), which is a major curcuminoid. The most detailed studies using curcumin include anti-inflammatory, antioxidant, anticarcinogenic, antiviral, and antiinfectious activities. In addition, the wound healing and detoxifying properties of curcumin have also received considerable attention. As a result of extensive research on the therapeutic properties of curcumin, some understanding on the cellular, molecular, and biochemical mechanism of action of curcumin is emerging. These findings are summarized in this review.

Antibacterial and antifungal activities from leaf extracts of Cassia fistula l.: An ethnomedicinal plant.

Abstract: This study was carried out with an objective to investigate the antibacterial and antifungal potentials of leaves of Cassia fistula Linn. The aim of the study is to assess the antimicrobial activity and to determine the zone of inhibition of extracts on some bacterial and fungal strains. In the present study, the microbial activity of hydroalcohol extracts of leaves of Cassia fistula Linn. (an ethnomedicinal plant) was evaluated for potential antimicrobial activity against medically important bacterial and fungal strains. The antimicrobial activity was determined in the extracts using agar disc diffusion method. The antibacterial and antifungal activities of extracts (5, 25, 50, 100, 250 ΅g/ml) of Cassia fistula were tested against two Gram-positive--Staphylococcus aureus, Streptococcus pyogenes; two Gram-negative--Escherichia coli, Pseudomonas aeruginosa human pathogenic bacteria; and three fungal strains--Aspergillus niger, Aspergillus clavatus, Candida albicans. Zone of inhibition of extracts were compared with that of different standards like ampicillin, ciprofloxacin, norfloxacin, and chloramphenicol for antibacterial activity and nystatin and griseofulvin for antifungal activity. The results showed that the remarkable inhibition of the bacterial growth was shown against the tested organisms. The phytochemical analyses of the plants were carried out. The microbial activity of the Cassia fistula was due to the presence of various secondary metabolites. Hence, these plants can be used to discover bioactive natural products that may serve as leads in the development of new pharmaceuticals research activities.

Phytochemical constituents of Cassia fistula

Abstract: Since the advent of modern drug treatments, traditional medicine has greatly receded in occidental societies. Moreover, only a limited number of medicinal plants have received detailed scientific scrutiny thereby prompting the World Health Organisation to recommend that this area be comprehensively investigated. Cassia fistula Linn is used extensively in various parts of the world against a wide range of ailments, the synergistic action of its metabolite production being most probably responsible for the plant’s beneficial effects. This paper reviews the primary and secondary metabolite composition of vegetative and reproductive plant parts and cell cultures thereby derived, with emphasis on potent phenolic antioxidants such as anthraquinones, flavonoids and flavan-3-ol derivatives. This paper also appraises the antioxidant and free radical propensities of plant parts and cell culture extracts. The data so far generated clearly sets the basis for a clearer understanding of the phytochemistry of the plant and derived cultures and opens the possibility of the potential utilization of the phenolic rich extracts from medicinal plants in food system or as prophylactics in nutritional/food supplement programs. Thus traditional medicinal plant- derived antioxidants may protect against a number of diseases and reduce oxidation processes in food systems. In order to establish this, it is imperative to measure the markers of baseline oxidative stress particularly in human health and disease and examine how they are affected by supplementation with pure compounds or complex plant extracts from the traditional medicinal plants.

Updated recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests.

Abstract: In 2008 we published recommendations on chemicals that would be appropriate to evaluate the sensitivity and specificity of new/modified mammalian cell genotoxicity tests, in particular to avoid misleading positive results. In light of new data it is appropriate to update these lists of chemicals. An expert panel was convened and has revised the recommended chemicals to fit the following different sets of characteristics: • Group 1: chemicals that should be detected as positive in in vitro mammalian cell genotoxicity tests. Chemicals in this group are all in vivo genotoxins at one or more endpoints, either due to DNA-reactive or non DNA-reactive mechanisms. Many are known carcinogens with a mutagenic mode of action, but a sub-class of probable aneugens has been introduced. • Group 2: chemicals that should give negative results in in vitro mammalian cell genotoxicity tests. Chemicals in this group are usually negative in vivo and non-DNA-reactive. They are either non-carcinogenic or rodent carcinogens with a non-mutagenic mode of action. • Group 3: chemicals that should give negative results in in vitro mammalian cell genotoxicity tests, but have been reported to induce gene mutations in mouse lymphoma cells, chromosomal aberrations or micronuclei, often at high concentrations or at high levels of cytotoxicity. Chemicals in this group are generally negative in vivo and negative in the Ames test. They are either non-carcinogenic or rodent carcinogens with an accepted non-mutagenic mode of action. This group contains comments as to any conditions that can be identified under which misleading positive results are likely to occur. This paper, therefore, updates these three recommended lists of chemicals and describes how these should be used for any test evaluation program.

Effects of the antioxidants curcumin and vitamin C on cisplatin-induced clastogenesis in Wistar rat bone marrow cells

Abstract: The use of dietary antioxidants to prevent antitumor agent-induced chromosomal damage in nontumor cells is currently eliciting considerable interest. Curcumin (CMN) is a dietary antioxidant that has been reported to protect against clastogenesis in in vivo and in vitro assays. This study was undertaken to investigate the modulatory effects of CMN on cisplatin-induced chromosomal aberrations in Wistar rat bone marrow cells and whether there is any potentiation of these effects with the combination between CMN and vitamin C (VC), which has been reported to reduce the clastogenic effect of many antitumor agents in in vivo assays. Animals treated with CMN plus a single dose of cisplatin, at 18, 24 or 72 h following treatment, presented a statistically significant reduction in the total amount of chromosomal damage and in the number of abnormal metaphases. The results also indicate that the combination between antioxidants would not be effective in protecting against cisplatin-induced chromosomal damage in animals sacrificed 24 h after cisplatin treatment. Under the present experimental conditions, CMN could prevent cisplatin-induced clastogenesis by acting as a free radical scavenger.