Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. (Araliaceae) as an adaptogen: a closer look.

The adaptogen concept is examined from an historical, biological, chemical, pharmacological and medical perspective using a wide variety of primary and secondary literature. The definition of an adaptogen first proposed by Soviet scientists in the late 1950s, namely that an adaptogen is any substance that exerts effects on both sick and healthy individuals by 'correcting' any dysfunction(s) without producing unwanted side effects, was used as a point of departure. We attempted to identify critically what an adaptogen supposedly does and to determine whether the word embodies in and of itself any concept(s) acceptable to western conventional (allopathic) medicine. Special attention was paid to the reported pharmacological effects of the 'adaptogen-containing plant' Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. (Araliaceae), referred to by some as 'Siberian ginseng', and to its secondary chemical composition. We conclude that so far as specific pharmacological activities are concerned there are a number of valid arguments for equating the action of so-called adaptogens with those of medicinal agents that have activities as anti-oxidants, and/or anti-cancerogenic, immunomodulatory and hypocholesteroletic as well as hypoglycemic and choleretic action. However, 'adaptogens' and 'anti-oxidants' etc. also show significant dissimilarities and these are discussed. Significantly, the classical definition of an adaptogen has much in common with views currently being invoked to describe and explain the 'placebo effect'. Nevertheless, the chemistry of the secondary compounds of Eleutherococcus isolated thus far and their pharmacological effects support our hypothesis that the reported beneficial effects of adaptogens derive from their capacity to exert protective and/or inhibitory action against free radicals. An inventory of the secondary substances contained in Eleutherococcus discloses a potential for a wide range of activities reported from work on cultured cell lines, small laboratory animals and human subjects. Much of the cited work (although not all) has been published in peer-reviewed journals. Six compounds show various levels of activity as anti-oxidants, four show anti-cancer action, three show hypocholesterolemic activity, two show immunostimulatory effects, one has choleretic activity and one has the ability to decrease/moderate insulin levels, one has activity as a radioprotectant, one shows anti-inflammatory and anti-pyretic activities and yet another has shown activity as an antibacterial agent. Some of the compounds show more than one pharmacological effect and some show similar effects although they belong to different chemical classes. Clearly, Eleutherococcus contains pharmacologically active compounds but one wishes that the term adaptogen could be dropped from the literature because it is vague and conveys no insights into the mechanism(s) of action. If a precise action can be attributed to it, then the exact term for said action should obviously be used; if not, we strongly urge that generalities be avoided. Also, comparison of Eleutherococcus with the more familiar Panax ginseng C.A. Meyer (Araliaceae), 'true ginseng' has underscored that they differ considerably chemically and pharmacologically and cannot be justifiably considered as mutually interchangeable. Accordingly, we recommend that the designation 'Siberian ginseng' be dropped and be replaced with 'Eleutherococcus'. In the case of both Eleutherococcus and true ginseng, problems inherent in herbal preparation use include inconsistencies not only in terms of indications for use, but in the nomenclature of constituent chemical compounds, standardization, dosage and product labeling. (ABSTRACT TRUNCATED)

Determination of unbound platinum after oxaliplatin administration: comparison of currently available methods and influence of various parameters.

Variations in plasma protein binding may have profound effects on both disposition and activity of drugs, especially for those which are tightly bound to proteins, such as anticancer platinum derivatives. Methods of separation of the non-protein-bound fraction and some technical parameters may influence the results. We have compared ultrafiltration and ultracentrifugation, as well as the effect of potentially interfering factors, upon the determination of the plasma unbound platinum fraction after oxaliplatin administration to cancer patients. Ultrafiltration and ultracentrifugation provided very closely correlated results, so that either technique can be used. The ultrafiltration cut-off (3000-30,000 Da) devices, the type of tube for blood sampling and the type of anticoagulant (none, lithium heparinate or EDTA) did not influence the results markedly. In contrast, results were greatly influenced by freezing: erratic results were obtained on thawed plasmas when compared with those on fresh serum or plasma. Consequences may be important in usual practice, since many pharmacokinetic studies are carried out in multicentric trials with plasma processing centralized in one reference laboratory. The methods for the determination of protein-drug binding should be standardized and guidelines elaborated where optimal conditions for each type of binding assay are given.

Vinorelbine (Navelbine). A new semisynthetic vinca alkaloid.

Vinorelbine (Navelbine) is a new, semisynthetic 5'Nor-vinca-alkaloid, modified on the catharantine ring, developed by Pierre Fabre Médicament. Vinorelbine is a potent as the other vinca alkaloids to inhibit mitotic microtubule polymerization. On the other hand, its activity is lower on axonal microtubule. Preclinical studies have shown its broad spectrum of activity in vitro and its antitumoral efficacy comparable or higher to that of other vinca alkaloids against murine tumors and in xenograft models. The main experimental toxicity of vinorelbine is a reversible leucopenia. No neurotoxicity was evidenced in rats, dogs and monkeys. After i.v. injection in patients, the plasma kinetic is described by a tricompartimental model with a high clearance, a very large volume of distribution and a long terminal half life, intermediate between vincristine and vinblastine. Tissue uptake of vinorelbine is very intense, probably related to its high liposolubility, leading to high tissue concentration compared to plasma. Phase I trial using weekly i.v. administration demonstrated a maximal tolerated dose (MTD) of 27.5 to 35.4 mg/m2 and the recommended dose was established at 30 mg/m2 weekly. In Phase II studies, Vinorelbine was shown to be effective in at least 4 types of cancer: Non-small cell lung cancer (remission rate: 33%), breast cancer (45%), advanced ovarian cancer (15% in heavily pretreated patients), Hodgkin's disease (90%). In all the trials, side effects are generally limited to a reversible and non-cumulative leucopenia. Neurotoxicity appears to be mild, similar to that observed with vinblastine and much less severe than with vincristine. No evidence of cardiac, pulmonary, renal, hepatic or other organ system toxicity has emerged.(ABSTRACT TRUNCATED AT 250 WORDS)

Advances in vinca-alkaloids: Navelbine.

Vinorelbine (Navelbine) is a new semisynthetic vinca alkaloid which chemically differs from vinblastine by substitutions on the catharantine moiety of the molecule. It has shown promising experimental antitumor activity against experimental murine tumors as well as continuous cell lines of human neoplastic origin and human tumor xenografts in nude mice. Acute subacute and chronic toxicity extensively studied in rodents, dogs and primate has shown that hematotoxicity was almost the sole side-effect; neurotoxicity appears very limited. Almost exclusive affinity of NVB for mitotic tubulin and tubulin associated protein accounts for this pattern of toxicity. Phase I and II studies have been conducted in humans. Dose limiting side-effect appears to be neutropenia: the drug is slightly emetogenic, induces little alopecia, almost no neurotoxicity, and no other toxicity. Although preliminary, results of phase II studies already suggest significant activity of NVB in non small lung cancer (33% response rate in 78 evaluable patients), advanced breast cancer (53% response rate in 33 pts without significant chemotherapy for the target progression) and Hodgkin's disease (90% response rate after 4 weekly courses in 31 pts). Thus extensive pharmacological studies and ongoing clinical studies confirm that chemical modifications of the catharantine moiety of vinca alcaloid can lead to active agents with broader spectrum of activity and easily manageable side effects.

Kat and its use: an historical perspective.

Of the many Old World plants or plant products which have potential for abuse, kat has probably been the least publicized in so-called more economically developed countries. Because kat has rather localized used and because, unlike opium and hashish it has no documented history or well-developed tradition dating from remote antiquity, few outside the confined areas of use even know about it. While kat has been, and still is, used in traditional medicine, it cannot boast of any great potential for development as a drug for use in Western societies. In short, the incentives for detailed, serious investigation until recently have been lacking. Even so, there is a considerable, albeit scattered, body of literature which might help provide renewed insights in approaching what is seen by some as an increasingly serious kat problem. A multidisciplinary historical overview of the use, abuse and sociology of this important plant is presented. Special emphasis is given to European early knowledge of, and evolution of attitudes towards kat use. Alleged past use and development of contemporary use patterns, effects, legal aspects, and chemical composition is covered from an historical perspective as well.

Karyological observations.

Root tips prepared for metaphase chromosome analysis from seedlings germinated under microgravity on the Space Shuttle (oats and mung bean) or which were exposed to space flight as very young seedlings (sunflower) have been examined. Experimental constraints did not permit pre-fixation in space with a cytostatic agent but arrest was achieved in the first division cycle on Earth after recovery. The number of cells in division was significantly depressed in all three species. Several chromosomal abnormalities were encountered in flight material. Bridge formation was seen in sunflower, as was aneuploidy. Breakage and fracture of chromosomes was prevalent in oats. No aberrant features could be detected in the chromosomes of mung bean. These results, although preliminary, should serve to alert investigators of the need to assess carefully as many aspects of cell division in higher plants exposed to space flight conditions as possible.