EFFECTS OF SEED PRIMING ON SENNOSIDE CONTENTS IN INVITRO GROWN LEAVES OF SENNA ALEXANDRINA MILL

Gowtham Kumaraguru, Malaiyandi Jayanthi and Girija Shanmugam*

ABSTRACT

Tinnevelly senna, popularly known as Senna alexandrina Mill, is a valuable plant drug in both the Ayurvedic and modern systems of medicine. Leaves and pods are used as natural laxatives. This plant's leaves contain sennosides A, B, C, and D, which are in high demand globally and are preferred as an ingredient in herbal tea in Asia. Sennoside is used as the most reliable and safest laxative agent. Pods and leaves of Senna plants are also used in the form of decoctions, powders, and many other herbal preparations. Senna plant is raised from seed and has a hard and tough seed coat. The sennoside contents varies among the plant parts. Poor germination of seeds affects its mass cultivation commercially. Therefore, in the present study seed priming was attempted using H2SO4, HCL, GA3, BAP to induce fast germination in in vitro using MS Basal media. Similarly, sennoside being the important compound of this plant hence analysed in different stages of the growth using the leaf sample. The anatomical, histochemical and micromorphological features of Senna invitro leaves were evaluated to confirm the morphological integrity. The present study also examined the effects of different seed priming on in-vitro seed germination, seedling development and sennoside contents in different growing stages (7th day, 14th day, 21st day and 30th days) from invitro leaves using RP-HPLC. The priming of Senna seeds found to be effective in breaking seed dormancy and the seeds primed in GA3 5.77 X 10-6 M showed the highest germination (98%) compared to all other priming treatments. Glandular and non-glandular trichomes were observed on both epidermal surfaces, although in greater number on the abaxial surface. Leaves were amphiestomatic with a single palisade layer and a slightly smaller spongy parenchyma. A comparison of all priming treatments shows no significant changes in anatomical and morphological characteristics. RP-HPLC quantification of sennoside found the highest levels of sennoside in 21st day old invitro-raised GA3 primed leaves at 22.69 mg/g. in Senna alexandrina, seed priming have improved the plant growth and secondary metabolite content along with germination and seed emergence.

Keywords: Laxative, HPLC, Gibberellic acid.