The antigonadotropic activity of I. The lack of steroid-like activity at the receptor level

Previous work has demonstrated that stem bark extracts of Combretodendron macrocarpum (Barringtoniaceae), Cola nitida (Sterculiaceae), Afrormosia laxiflora and Pterocarpus erinaceus (Fabaceae) blocked the oestrus cycle of female rats through antigonadotropic activity. Moreover, a study of the plant substances responsible for these effects revealed the presence of phyto-anti-oestrogens in these plant extracts. In order to explain the mechanism by which these substances exert their antifertility actions, the interaction of the plant extract with oestrogen and progesterone receptors was studied. All crude extracts exerted inhibition of ((3)H)-oestradiol or ((3)H)-Organon binding to their respective receptors but their relative affinities were much lower than those of oestradiol or progesterone. Respective efficiencies of plant extracts in competing for the oestrogen receptor were as follows: A. laxiflora > P. erinaceus > C. macrocarpum > C. nitida. The efficiency order of competition for the progestin receptor was different to that of oestrogen. The most potent competitor was C. macrocarpum extract, followed by P. erinaceus, C. nitida and A. laxiflora. Moreover, the interaction between oestradiol and plant extracts with the oestrogen receptor was determined to be competitive only for C. macrocarpum and A. laxiflora, whereas all compounds produced a competitive inhibition on the progestin receptor binding. These results suggest that the plant extract binding site was the same site as for the steroid. These results suggest also that crude plant extracts may interfere with natural oestrogen and/or progestagen in vivo by binding to steroid receptors.

Section: Discussionsupporting

confidence: 56%

Interaction of some traditional plant extracts with uterine oestrogen or progestin receptors

Benie

Thieulant

2003

“…In the same way, this author added that Pisum sativum (Fabacea) seed consumption provoked sterility in Tibetin women. Further pharmaceutical studies showed that L. ruderale contains an antigonadotropic substance, lithospermic acid (Findley and Jacobs, 1980) and P. sativum seed (m-xylohydroquinon) is capable of provoking fetal resorption (Soejarto and Bingel, 1979).…”

Section: Introductionmentioning

confidence: 99%

Effects of some traditional plant extracts on rat oestrous cycle compared with Clomid

Benie

Duval

Thieulant

2003

It is well known that the plant kingdom contains numerous bioactive substances affecting the regulation of reproduction. The present study was undertaken to examine the putative contraceptive effects of three traditional plant extracts from Côte d'Ivoire Pharmacopea. It concerns Afrormosia laxiflora (Papilionacea), Pterocarpus erinaceus (Papilionacea) and Cola nitida (Sterculiacea) stem bark. Data showed that treatment of rats with these plant extracts induced ovulation and oestrous cycle blockade at the dioestrous II stage. The analysis of the principal hormones involved in oestrous cycle regulation showed that the plant extracts decreased gonadotropin release (both LH and FSH). In fact, A. laxiflora, P. erinaceus and C. nitida extracts inhibited gonadotropin release as an antiestrogen-like substance.

“…The chemically defined napthaquinones found in these roots are shown in Table 1. The amount of each of the enantiomeric napthaquinones, shikonin (R-configuration), alkannin (S-configuration) and chemically related derivatives have been observed to vary in Zicao extracts.We focus on the chemically defined compounds in this review.Crude Zicao is an efficacious antiinflammatory (Hayashi, 1977a) and antigonadotropic agent (Findley, 1981;Findley and Jacobs, 1980;Winterhoff et al, 1988), and inhibition of thyroid and pituitary hormone effects have been measured (Auf'mkolk et al, 1984;Winterhoff et al, 1983;Sourgens et al, 1982). It also displays anti-HIV-1 activity (Ueba et al, 1993;Yamasaki et al, 1993).…”

mentioning

confidence: 99%

Cellular pharmacology studies of shikonin derivatives

Chen

Yang

Oppenheim

et al. 2002

371

274

The naphthoquinone pigment, shikonin, isolated from Lithospermum erythrorhizon Sieb. et Zucc.(Boraginaceae) and its derivatives are the active components isolated from the Chinese herbal therapeutic, Zicao. Historically, Zicao root extracts have been used to treat macular eruption, measles, sore-throat, carbuncles and burns. Multiple pharmacological actions have been attributed to shikonin, e.g. antiinflammatory, antigonadotropic and anti-HIV-1 activity. In this review, several therapeutic applications of shikonin will be summarized including its pleiotropic, antiinflammatory and antitumour effects. Widely diverse and sometimes conflicting activities have been attributed to shikonin, e.g. wound healing, enhanced granuloma formation, suppression of local acute inflammatory reactions, inhibition of angiogenesis, inhibition of select chemokine ligands, inhibition of DNA topoisomerase activity, inhibition of platelet activation and antimicrobial activity. Comparison of the various reported mechanisms of action for shikonin lead us to hypothesize that shikonin is an effective inhibitor of protein-protein interaction with multiple targets in both the intracellular and extracellular compartments. This general inhibitory effect can account for the broad spectrum of shikonin biological and pharmacological activities.