A simplified but effective method for the quality control of medicinal plants by planar chromatography.

Three of the factors limiting the rational use of herbal medicine are uncertainty on effectivity, uncertainty on safety and variation in quality of the product. Because many herbal medicines have been used over centuries by indigenous peoples, the safety and effectivity is frequently not such a big concern. With more people collecting and distributing herbal medicine, the offered product is however, frequently not what the label indicates either through a genuine mistake, but also through fraud especially where expensive herbal medicine is concerned. Some wrong identifications have already led to serious side effects and deaths. Planar chromatography or thin layer chromatography [TLC] is widely used to verify the identity of plant extracts by determining the chemical fingerprint of the extracts. In a leading publication 17 different extractants, 41 solvent systems and 44 spray reagents have been used to verify the identity of important herbal preparations. We investigated whether a simplified system could not be developed to aid small laboratories in identifying different herbal medicines. We compared the efficacy of different extractants, identified and developed three TLC solvent systems that would separate compounds with low, medium and high polarity and then also investigated the use of several spray reagents. With acetone as extractant and benzene:ethanol:ammonia [9:1:0.1], chloroform:ethylacetate:formic acid [5:4:1] and ethylacetate:methanol:water [10:1.35:1] as TLC solvent system and vanillin-sulphuric acid as spray reagent the identity of 81 samples of more than 50 herbal preparations could be verified on the basis of the chromatograms. The same product from different suppliers usually gave similar chromatograms. More importantly in several cases it was clear that products with the same label were so different that a mistake must have occurred in the labelling. This method has found application in the quality control of the most important African medicinal plants in the recently published African Herbal Pharmacopoeia produced by the Association for African Medicinal Plant Standards (AAMPS).

L-methionine as immune supportive supplement: a clinical evaluation.

The objective of the study was to test L-methioinine as a possible immune supportive supplement in HIV infected patients by means of a clinical study. A double-blind, placebo-controlled study was designed. The patients (n = 253) from four different trial centres were randomly divided into two groups, active and placebo, and regularly assessed by clinical and safety parameters. After six months from commencement, clinically and statistically significant differences were observed. The females of the active treatment group presented with a decreased level of decline in their CD4 counts (p = 0.0027), so also the patients of Centre 1 (p = 0.0377). All patients were placed onto active treatment after 12 months and were followed up for 48 months after the trial started. The same tendencies could be observed in the group as a whole, with no serious side effects directly associated to treatment. The study confirmed the supportive role of L-methionine in immune-compromised or deficient patients.

The influence of porphyrogenic drugs on the glyoxalase enzymes.

A variety of drugs, known to induce acute attacks in porphyric patients has been found to inhibit the glyoxalase pathway. Glyoxalase I is competitively inhibited by sulphadimidine, oxytetracycline, chloramphenicol, etc. Allylisopropyl acetamide (AIA) seems to inhibit glyoxalase II. This inhibition could play a contributing role in the overproduction of porphyrins in porphyria and thus help explain the mechanism of induction of porphyric attacks. The results indicate, that the Heme pathway and the glyoxalase cycle are closely connected.

Chicken eggshell porphyrins and the glyoxalase pathway: its possible physiological role.

1. The plasma 4,5-dioxovaleric acid (DOVA) levels of two different breeds of chicken were determined and found to be higher in the group with a higher porphyrin eggshell content. 2. The erythrocyte and uterus glyoxalase II activity, investigated by means of a new spectrophotometric method, was found to be significantly higher in the group with a low porphyrin eggshell content. 3. A comparative genetic study of two chicken populations, one with white and one with dark eggshells, showed different gene frequencies for the glyoxalase I polymorphism. 4. An interpretation of these data suggests that the glyoxalase pathway may be involved in the metabolism of early porphyrin precursors.