Louis Cosson

Relative importance of growth and light level on terpene content of Ginkgo biloba

Growth of young Ginkgo biloba cultivated in a greenhouse, in natural light (varying between 125 and 1100 μE m−2 s−1), at 24-17° and evolution of the terpene content (ginkgolides A, B, C, J and bilobalide) in leaves, shoots and roots were observed at the same moments during the first three years of life. Leaves accumulate more terpenes than roots and especially shoots. Annual mean concentrations of terpenes in leaves remain constant during the first three years of Ginkgo development, whereas those of roots and shoots evenly decrease. During one vegetative season, terpene content fluctuated significantly in leaves. This is mainly due to seasonal variations of ginkgolide A and bilobalide, which reach a maximum value at the end of summer or at the beginning of autumn. When the plants are cultivated in a climate chamber, in constant artificial light with medium photonic flux (250 μE m−2 s−1) at the same temperatures, the ginkgolide and bilobalide content in leaves remains low and constant. The level of terpene accumulation in G. biloba leaves may be linked to the photonic level and not to leaf or plant growth or to a specific stage of organs.

Glucosylation of thiocolchicine by a cell suspension culture of Centella asiatica

Abstract Thiocolchicine, a hemisynthetic substrate obtained from natural colchicine, was converted to its 2- O - and 3- O -monoglucosyl derivatives by cell suspension cultures of Centella asiatica . In view of its cytotoxic effects, the thiocolchicine was administered to seven-day-old suspension cultures. The amounts and the compartmentation of products were then measured over a 12-day period. The results showed the intracellular localization of glucosides.

Biotransformation of a synthetic compound, 1,5-diphenylsulphinyl-3-methyl-3-nitropentane, by cell suspensions of Catharanthus roseus

Abstract Biotransformation of a synthetic substrate, 1,5-diphenylsulphinyl-3-methyl-3-nitropentane, by cell suspension cultures of Catharanthus roseus was investigated. It was found that this substrate was (i) incorporated into cells and (ii) converted within three days into a new product, 1-phenylsulphonyl-5-phenylsulphinyl-3-methyl-3-nitropentane through a regioselective oxidizing process not previously described. This original organic substrate used for bioconversion is entirely synthetic and the functions (nitro, sulphoxide) are rarely involved in biotransformation studies. Such a biotechnological process could be of great interest for the production of new chemical compounds.

The constituents ofCannabis sativa pollen

ConclusionThe pollen ofCannabis sativa L. was rich in cannabinoids and particularly in THC and THCA, the latter being able to be transformed into physiologically active THC. Climatic factors and particularly temperature played an important role, since the THC content at 24° C 16 h was 30 times as great as at 22° C 12° C 16h.Determinations of the phenol compounds in the corresponding flowering heads had not been completed, but those that had been finished showed that the optimum content was given by plants cultivated at 24° C 16 h.The highest concentration of alkaloid type substances was also given under this climatic regime: these substances were different from choline and trigonelline and studies were under way to identify them.With regard to the flavonoids that were examined by two-dimensional paper chromatography, two principal spots were detected corresponding to two glycosides. After hydrochloric acid hydrolysis two different genins were identified as apigenin and luteolin respectively. These flavone glycosides were also found in the leaves together with several others, and a further study is being made of them the results of which will be published shortly.

Biotransformation of ethyl 2-acetylamino-2-carbethoxy- 4-(phenylsulphinyl)-butanoate by cell suspension of Catharanthus roseus and Thevetia nefiifolia

Abstract Biotransformation of the synthetic substrate, ethyl 2-acetylamino-2-carbethoxy-4-(phenylsuphinyl)- butanoate, by cell suspension cultures of Catharanthus roseus and Thevetia neriifolia was investigated. It was found that only three of six cell lines of T. neriifolia tested biotransformed the test substrate into a new product, ethyl 2-acetylamino-2-carbethoxy-4-(phenylsulphonyl)-butanoate, through a selective oxidizing process not previously described. Such a biotechnological process could be of great interest for the production of new chemical compounds.

Mise en évidence de deux types chimiques chez le Cannabis sativa originaire d'afrique du sud

Abstract Culture in a phytotron of Cannabis sativa L. originating from S. Africa revealed the presence of two chemotypes varying in concentration of tetrahy

Cardenolide Formation in Cell Suspension Cultures of Thevetia peruviana (Pers.) K. Schum. (synonym Thevetia neriifolia Juss.)

Abstract Six cell suspension cultures established from different organs of Thevetia peruviana were initiated under various growth conditions. Even after two years of subculture, cardenolides proved to be present in all the strains. The cardenolide content varied from one strain to another according to the nature of the original explant and was always lower in comparison with that of the seeds of the original plant. Kinetic studies showed that the cardenolide content varied over a complete cycle of culture.

Selection and improvement of Datura innoxia Mill.-Morphological variability in in vitro propagated plants

SummaryTo select high-alkaloid-producing plants, we have developed an experimental model producing the largest possible number of plants differing from the source plant. On the basis of the commonly accepted idea that the formation of an intermediate callus would increase chances of recovering altered plants, we propagated Datura innoxia Mill, through axillary buds (micropropagation) and through regeneration from explants giving a callus at various degrees of development before bud shoots are differenciated. Seventy-eight plants were obtained; their morphological characteristics were observed at the first floral bud stage. Numerous plants, including those propagated through axillary buds, were smaller and had less leaves than seed-grown plants. Very peculiar features (flowers, leaves, ramifications) were observed in five plants (“abnormal plants”): two were produced from thin cell layers without intermediate callus, three from internodes after formation of a well-developed intermediate callus. No “abnorma...