Improvement of the host resistance by using hazard free chemical elicitors is emerging as an alternative approach in the field of plant disease management. In our present work, we have screened the efficacy and possible mechanism of abiogenic elicitors like Dipotassium hydrogen orthophosphate (K 2 HPO 4 ), Oxalic acid (OA), Isonicotinic acid (INA), Salicylic acid (SA), Acetylsalicylate (AS), Arachidonic acid (AA) and Calcium chloride (CaCl 2 ) to stimulate innate immune responses in Lycopersicum esculentum Mill. Excised tomato leaves, treated with elicitors at three different concentrations, were found to stimulate defense and antioxidative enzymes, total phenol and flavonoid content after 24 h of incubation. CaCl 2 (0.5 %) followed by INA (2.5 mM) were found most effective in activation of all such defense molecules in tomato leaves. Furthermore, nitric oxide (NO), a key gaseous mediator in plant defense signaling, was also measured after subsequent elicitor application. Higher doses of elicitors showed an elevated level of reactive oxygen species (ROS) generation, enhanced lipid peroxidation rate and proline content, which indicates the extent of abiotic stress generation on the leaves. However, ROS production, lipid peroxidation rate and proline concentration remain significantly reduced as a result of CaCl 2 (0.5 %) and INA (2.5 mM) application. A sharp increase of total chlorophyll content was also recorded due to treatment of CaCl 2 (0.5 %). These results demonstrate the effects of different abiogenic elicitors to regulate the production of defense molecules. Results also suggest that among all such chemicals, CaCl 2 (0.5 %) and INA (2.5 mM) can be used as a potential elicitor in organic farming of tomato.

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Ocimum sanctum Linn (OS), is the medicinal herb belonging to the Lamiaceae family, well-known as the ‘Holi Basil’ or ‘Tulsi”. It has been a part of ayurveda and Indian culture for its tremendous ethnomedicinal significance as it is employed to cure common cough and cold along with bronchitis, skin diseases, insect bite etc. The leaves of OS in particular are widely used for the treatment of cancer. Approximately 15 different types of biologically active chemicals have been extracted, purified and identified from this medicinal herb. The anticancer properties of the crude and purified products from OS have been studied extensively over decades. They showed tumor suppressive, radioprotective, chemo-preventive, anti-metastatic, anti-angiogenic and apoptotic effect on various types of cancer. This review summarizes the anticancer effect and mechanism of the purified products and extract obtained from OS on various cancers like breast, colon, lung, liver etc. The summarized report would help to fine-tune our understanding on the anti-cancer properties of OS that might open up new horizon in developing natural product-based cost- efficient cancer drug.