HPTLC densitometric evaluation of tissue culture extracts of Nothapodytes foetida compared to conventional extracts for camptothecin content and antimicrobial activity.

Tissue culture technique is becoming popular because of its well-known ability to enhance the content of secondary metabolites in plants. Callus tissue cultures of Nothapodytes foetida were developed using 250 different medium compositions to optimize this procedure. Methanolic extracts of callus (MEC) and of various parts of N. foetida were comparatively analyzed for camptothecin content, and a high performance thin layer chromatography method was developed for its quantitation. Chloroform-ethylacetate-methanol (4 : 5 : 0.5 v/v) was used as the mobile phase. The method was validated for linearity, precision (interday and intraday), repeatability, limit of detection (LOD), limit of quantitation (LOQ), and accuracy. The relationship between the concentration of standard solutions and the peak response was linear within the range of 80 to 480 ng/spot with a correlation coefficient of 0.998 +/- 0.020. Instrumental precision was evaluated as 0.54 (% CV). Repeatability of sample and standard were estimated to be 1.08 and 1.01 (% CV), and LOD and LOQ were found to be 40 and 80 ng/spot, respectively. The accuracy of the method was checked out by a recovery study and the average percentage recovery was calculated as being 99.13 %. The methanolic extract of callus grown in tissue culture with medium composition picloram + thidiazuron + gibberellic acid (1 : 1 : 4; MEC-PTG) showed a higher percentage of camptothecin (5.74 % w/v) than the methanolic extract of fruits (3.56 % w/w), leaves (1.56 % w/w), stem (1.19 % w/w), and root (1.11 % w/w). The results of the antimicrobial screening indicate that MEC-PTG exhibited maximum activity against all microorganisms. Among the fungi tested, MEC-PTG showed maximum activity against A. niger and C. albicans (MIC value 10 microg/mL) whereas among bacteria strains, its activity was highest against B. subtilis and S. lutea (MIC 20 microg/mL).