Though there are still some problems of growth and productivity which are to be overcome to make commercial products cheaper, there are already some secondary metabolite products commercially, obtained mainly by Japanese, Americans, W. Germans. Mitusui Pharmaceutical Industries of Japan have started producing ‘Shikonin’ from Lithospermum erythrorhizon.
Shikonin, a red pigment is an anti-bacterial and anti-inflammmatory compound used widely in Japanese pharmacopea. Since it is also a safe red dye, it is now being marketed as ‘bio- lipstics’. Bethesda Research Laboratory, Maryland, U.S.A. is marketing ‘Phosphodiesterase’ obtained from tobacco tissue cultures. The production of ‘berberin’ used against stomach distress, by ‘Coptis japonica’ is likely to be industrialized.
The production of two or more products from one culture is being explored, for instance, tobacco cells cultured in 20,000 litre fermentors are being used for producing ubiquinone (used against heart ailments), biotin, and low tar tobacco for cigarettes.
Future Prospects of Commercial Production: B. Kaul and E.T. Staba of College of Pharmacy, University of Minneseta (U.S.A.) have reported that ‘diosgenin’, a major raw material for manufacture of cortricosteroids and steroid contraceptives, can be obtained from ‘Dioscrea deltoidea (Yam) using tissue culture technique. The tissue culture of valuable Chinese drug ‘Ginseng’ can result in ginsenosides in large amounts (more than 20% of dry weight as crude saponins) in Japan.
Plant tissue culture can produce certain types of quinone. The callus culture of Cassia tora (Fetid cassia) contain more than ten times as much as quinones as anthraquinones. Similar results have been reported using suspension cultures of Morinda citrifolia (Indian Mulberry) and Cassia angustigolia (Indian Senna).
Ubiquinone-10 used us a remedy for congestive heart failure has been produced by Nicotiana (Tobacco) cell/tissue suspension cultures at a rate of 360 kg/hectare dry weight which is higher than that by microbes.
Similarly, the content of napthaquinone pigments used for the treatment of skin diseases, burns and haemorrhoids, has been successfully increased in callus culture of Lithospermum erythrorhizon (Gromwell). The increase in the amount of napthaquinones through callus culture is important especially because of the decreasing availability and unsuccessful cultivation of the plant.
Screening of various tissue cultures by bioassays for definite pharmaceutical activities may be an effective method for exploiting active substances produced by cultured tissues. For instance, some of callus tissues isolated from Emblica officinalis (Amla) and Isodan Japonicus produce proteinase inhibitor showing a marked antiplasmin activity. Similarly, dried callus pf vinca rosea (Peri winkle) is a cure for coccidium disease of chicks and a powerful prophylactic against pathogenic protozoa.