Thesis (M.Sc.)--Chulalongkorn University, 2009

Licorice (Glycyrrhiza glabra Linn.) is a perennial plant native to Southern Europe and parts of Asia, used as a non-nutritional sweetener but with numerous reported pharmacological effects, including anti-inflammatory and antiviral properties. The study was aimed to optimize an in vitro micropropagation protocol of G. glabra plants from in vitro shoot tips, the effect of medium types, medium strength of salt base, sucrose concentration, cytokinin and auxin types were tested for the ability to support the growth of shoot tips in culture. The most suitable medium for G. glabra plant growth and development was 1/2 - strength B5 salt and 30 gL[superscript -1] sugar. However, MS medium supported a superior proliferation rate. MS medium supplemented with 0.5 mgL[superscript -1] of BA produced the maximum of shoots (4.75) per explant. The highest efficiency of root formation occurred in the 1/2-strength B5 medium containing 5.0 mgL[superscript -1] of either IAA or IBA after six weeks of culture. The survival rate of plantlets was 95% when used either garden soil or vermiculite as substrate culture. The glycyrrhizin contents were analyzed by HPLC. The production of glycyrrhizin in culture using 1/2- strength B5 medium supplemented with 5.0 mgL-1IAA increased with time up to week 8 reaching 27.57 ± 0.66 mug g[superscript -1] dry wt as compared with control (13.66 ± 1.21 µg g[superscript -1] dry wt).