Advancing Caribbean herbs in the 21st century

Just as elsewhere in the tropics, most plants used in traditional medicine in the Caribbean region have never been evaluated systematically for their theraputic qualities. It is recognized that some of them can become the raw materials for a future Caribbean herbal industry; and these are issues, which concern the Caribbean Association of Researchers and Herbal Practitioners (CARAPA). These were among the issues considered under the theme "Advancing Caribbean herbs in the 21st century" at the Sixth International conference of CARAPA on "Herbal medicine in the Caribbean". Over the three-day period, about one hundred and fifty registered participants attended the conference, including eight residents coming from Tobago, and twenty-six persons from fourteen countries outside the Republic of Trinidad and Tobago. Their valuable contributions are reflected in this document, which contains over thirty papers distributed across the following sections: Science and the Commercialization of Herbs; Scientific evaluation of medicinal plant extracts; Issues for a Caribbean herbal industry and Continuing education in herbal medicine .... (AU)

Pharmacological evaluation of some local plant extracts claimed to be used abortifacients in folklore practice

OBJECTIVE: Several local plant extracts are used in folklore practice as abortifacients. The objectives was to determine the scientific basis, if any, for these claims. METHODS: Aqeous extracts were prepared from 6 plants collected from St.Thomas, Jamaica: Leonotis nepetifolia (LN), Mentha pulegium (MP), Phyllanthus amarus (PA), Stachytarpheta jamaicensis (SJ), Gliricidia sepium (GS) and Wedelia gracilis (WG). The extracts were tested for contractile activity on isolated mouse uteri maintained in de Jalons solution. The effects of indomethacin and atropine on the contractions were used to indicate the possible mechanism of action. RESULTS: Three plant extracts (LN, MP and PA) produced dose-dependent contractions of the non-pregnant and pregnant mouse uteri. No contractions were observed with the other three extracts (SJ, GS, and WG). The contractions produced by MP were significantly reduced by indomethacin (p<0.05) but not by atropine. Contractions produced by LN and MP were blocked by either drug. Pregnant mice given LN litterd with live offspring within 24 hours. CONCLUSIONS: Of the 6 plants evaluated, 3 contracted the uterus in vitro but only one (LN) had a significant action in vivo. The contractile effect of MP may possibly be mediated via prostaglandins. However, this plant extract showed significant toxicity in vivo. (AU)

The characterization of the activity of a bark extract from Fagara martinicensis on the rat vas deferens

OBJECTIVE: An aqueous extract made from the bark of Fagara martinicensis (family Rutaceae) was examined for its effect on the isolated rat vas deferens. METHOD: The investigation involved measurement of isometric tension in the prostatic and epididymal portions of the isolated rat vas deferens which was anchored in an organ bath with physiological solution. Non-cumulative doses of Fagara martinicensis (FM) were added to the bath and the effects examined in the presence of receptor antagonists to characterize the actions of FM. Results before and after antagonist additions were compared. RESULTS: Non-cumulative addition of FM (1.6 mg/ml to 14.1 mg/ml) produced contractions of both portions of the vas deferens, with the epididymal portion showing greater sensitivity to the effects of FM. The contractions consisted of a rhythmic component superimposed on a phasic and tonic component. All components of the contractions were abolished by prazosin (2.1 uM), a selective a1-adrenoreceptor antagonist, and therefore it was concluded that FM contractions are due to agonist activities on these receptors. Since stimulation of a1-adrenoreceptora results in the mobilization of extracellular calcium into the muscle, the involvement of extracellular calcium was investigated with calcium channel antagonist, nifedipine (0.11-6.0 uM). Nifedipine inhibited all components of the contraction. This effect indicates that entry of extracellular calcium into the muscle was involved in all components of the contraction and further confirms a1-adrenoreceptor agonist action of Fagara martinicensis. CONCLUSIONS: Fagara martinicensis may therefore be a potential source of drugs with a1-adrenoreceptor agonist properties. (AU)

The effect of Bromelia pinguin extract on the pregnant rat uterus

A non proteinaceous extract of Bromelia pinguin fruit was examined for activity on the rat uterus in vivo and in vitro. The in vivo experiments involved pregnant rats given the extract intraperitoneally. These rats did not abort nor were any foetal deformities observed. The extract inhibited spontaneous activity of the pregnant rat uterus in vitro. The extract of Bromelia pinguin fruit may have some utero-active compound which inhibits uterine motility.(AU)

Screening of medicinal plants from Trinidad and Tobago for antimicrobial and insecticidal properties

Antibacterial activity in 51 extracts from 29 plant species currently used in traditional medicine in Trinidad and the neighbouring Caribbean islands was tested for by the agar dilution streak method using six bacteria: Escherichia coli, Pseudomonas aeruginosa. Salmonella tophimurium, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. The extracts from eight of the plants tested showed significant activity against one or more micro-organisms and the most susceptible bacterium was Staphylococcus aureus. In the bioassays for toxicity towards the Aedes aegypti mosquito the most effective plant extracts were from Justicia pectoralis, Manihot utilissima and Stachytarpheta jamaicensis.(AU)

Investigation of plants used in Jamaican folk medicine for anti-bacterial activity

We have started a systematic scientific study of folklore medicinal plants currently used as alternative medicine in Jamaican society. In this initial study, extracts of plants widely used by the islanders are studied for antibacterial activity against five common pathogens; Streptococcus group A, Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa and Escherichia coli. These studies revealed that 25 percent (approximately) of the plant extracts had antimicrobial activity against at least one of the microbes used. Subsequent to these observations, extracts from Mikania micrantha were examined in detail. This led to the isolation of two sesquiterpenoids, mikanolide and dihydromikanolide, with activity against S. aureus and C. albicans. The results suggest that traditional folk medicine could be used as a guide in our continuing search for new natural products with potential medicinal properties.(Au)

Angiotensin converting enzyme inhibiting and anti-dipsogenic activities of euphorbia hirta extracts

The methanol extract obtained from the leaves and stems of Euphorbia hirta inhibited the activity of angiotensin converting enzyme (ACE) by 90 percent and 50 percent at 500 ug and 160 ug respectively using enzyme linked immunosorbent assay (ELISA). The effect of the extract on thirst was examined using Wistar rats. Intraperitoneal administration of 10mg/100mg body wt of the extract significantly (p<0.05) decreased the amount of water consumed by rats. This effect lasted for 2 h.(AU)

Stimulation of insulin secretion by extracts of piper tuberculatum - abstract

Piper tuberculatum, locally known as candle-bush, is widely used in folk medicine in Trinidad and Tobago in the control of diabetes mellitus. It is commonly administered as a tea prepared from the leaves of the plant. This study was undertaken to investigate the hypoglycaemic activity (if any) of the plant, to identify and partially purify the active component and to obtain some information on the mechanism(s) of action. A methanol extract of leaves of the plant was screened for hypoglycaemic activity. The chloroform phase obtained from a chloroform form/H[2]O partition of the extract contained the active component which was further partially purified by column and thin-layer chromatography. Based on the chromatographic behaviour and HNMR spectroscopy, the active component was indentified as an amide alkaloid, most likely piplartine or a closely related derivative. The hypoglycaemic activity of the component, as tested on streptozotocin-diabetic rats, was found to be similar to that of an authentic sample of piplartine. The partially purified active component produced an increase in phospholipase C activity of the plasma membrane of pancreatic islet cells and induced insulin secretion in diabetic rats. The exact mechanism of the stimulation of insulin release requires further investigation but may be similar to that of sulphonylureas (AU)

Toxic effects of ackee oil (Blighia sapida L) following subacute administration to rats

Subacute intraperitoneal administration of the lipid portion of the unripe ackee arillus, referred to as "ackee oil", resulted in marked neutropenia (p<0.001) and increase in platelets (p<0.01) without anaemia, in rats. Blood urea, sodium amd aspartate aminotransferase levels were significantly decreased but glucose and bilirubin levels were similar to those of controls. The lungs showed areas of petechial haemorrhaghes and a dose-related perivascular and peribronchial mononuclear cell infiltration. The pulmonary toxicity may be interpreted as a hypersensitive reaction to ackee oil. Further research is in progress on the neutropenic effects of ackee oil. (AU)

The hypoglycaemic effect of annatto (bixa orellana) - abstract

In West Indian folklore, a number of plant extracts are utilised for medicinal purposes. One common malady so treated is diabetes mellitus. Some twenty (20) folk medicines (bush tea) were investigated as to their efficacy in lowering blood sugar levels in the anaesthetised dog model. The annatto (bixa orellana) when prepared as an oil suspension of the red seed coat was found to be quite a potent hypoglycaemic agent. It was further studied in order to purify the crude extract and possibly identify the pharmacologically active agent(s). The annatto seeds were percolated with chloroform until the bright red colour of the seed coat was removed. This extract was concentrated in vacua and the residue extracted selectively with 60 percent ethanol/water and petroleum ether. A final wine-red to orange viscous extract was used in the biological experiments. This partially purified petroleum ether extract was dissolved in corn oil (80 mg/kg body weight animal) and given to anaesthetized dogs via a stomach tube. After a residence time of one (1) hour, oral glucose tolerance tests were performed. The results showed hypoglycaemia in both the normal and streptozotocin diabetic dogs when compared to controls. Its effect is to delay the peaking of glucose after a meal and to increase the release of insulin in relation to blood glucose levels. The possibility of an effective hypoglycaemic principle in this extract increases pharmacological curiosity into this form of 'lay' treatment of diabetes mellitus. Detailed studies are continuing to identify and isolate the active component(s) (AU)

The discovery of the vinca alkaloids-chemotherapeutic agents against cancer

In folklore medicine, extracts of the leaves of the subtropical plant Catharanthus roseus (L.) G. Don (sometimes known as Madagascar periwinkle) were reputed to be useful in the treatment of diabetes. This review describes how attempts to verify the antidiabetic properties of the extracts led instead to the discovery and isolation of two complex indole alkaloids, vinblastine and vincristine, which are used in the clinical treatment of a variety of cancers. The two alkaloids, although structurally almost identical, nevertheless differ markedly in the type of tumors that they affect and in their toxic properties. These and related alkaloids have been the subject of many pharmacological and biochemical investigations both in vivo and in vitro in the search for improved cancer treatments. A model system used in these studies, a transplantable lymphoma in Noble strain rats designated Nb2 node, has serendipitously led to the development of a highly sensitive and specific bioassay for lactogenic hormones. (AU)

Inactivation of strongyloides stercoralis filariform larvae in vitro by six Jamaican plant extracts and three commercial antihelminthics

In vitro bioassay of (a) aqueous methanol extracts (AME) of the green leaves of mimosa (Mimosa pudica), love weed (Cuscuta americana), vervine (Stachytarpheta jamaicensis), chicken weed (Salvia serotina) and breadfruit (Artocarpus altilis); (b) methanol-water fraction (MWF) of breadfruit leaves, and (c) commercially available drugs albendazole, thiabendazole and levamisole were assayed for nematode inactivating potential, using filariform larvae of Strongyloides stercoralis. Test larvae were obtained from a 10-day-old charcoal coproculture. Bioassays were conducted in Locke's solution, using 100 larvae in each of three replicates. Inactivation was recorded microscopically at 1, 2, 6 and 12 hours, then every 24 hours up to 5 days' incubation. It(50) (time for inactivation of 50 percent of larvae) values read: levamisole and mimosa extract < 1 hour; love weed extract, approximately 2 hours; breadfruit (MWF), 9.5 hours; chicken weed, 20 hours; albendazole, 35 hours; breadfruit (AME), 49 hours; thiabendazole, 74 hours and vervine extract, 81.5 hours. It(95) values followed a similar trend, and were approximately double the It(50) measures. A potential role for locally available natural products in the treatment of strongyloidiasis is highlighted (AU)

Hash-oil manufacture: an important factor in the occurrence of adult burns in Jamaica

A retrospective study of burn patients admitted to the Cornwall Regional Hospital during the period 1982 to 1986 revealed that 21 patients sustained their burns during hash-oil manufacture. Hash-oil is the colloquial name for the extract from the ganja (marijuana) plant. The process of extraction is extremely hazardous as it involves the boiling of volatile liquid. Consequently, burns occur either due to scalds, flash, or, most commonly, flames. Young adult men are mainly affected, and more than 50 percent of them die as a result of their injury. (AU)

Effects of ackee fruit extracts on bronchomotor tone in rats

The unripe ackee fruit, when eaten, is known to cause serious clinical manifestations, including vomiting, hypoglycaemia and acidosis. The effects, of various extracts from the arilli of the unripe fruit (including hypoglyin-A) on the lungs from rats were examined in an in vitro preparation. All the extracts were found to induce moderately severe broncho-constriction, indicating a possible contribution of these effects to the observed toxicity of ackee (AU)

Toxicity of the hyperglycaemic-inducing extract of the Annatto (Bixa orellana) in the dog

The Annatto seed coat extract, which is commonly used in folklore in treating diabetes mellitus, has been investigated for its effects on blood sugar levels in the dog. An alkali-soluble hyperglycaemia-inducing fraction was detected, and detailed studies revealed toxic effects in the pancreas and liver accompanied by hyperglycaemia and apparent tendency to increased insulin levels. The toxicity was diminished by feeding riboflavin. The relevance of this finding points to a possible aetiological role in the development of malnutrition-related diabetes mellitus and also to the potential toxicity inherent in the widespread use of folklore medicines (AU)

Demonstration of anticonvulsant properties of an aqueous extract of Spirit Weed (Eryngium foetifdum L.)

Rats were used to investigate the anticonvulsant potential of two aqueous extracts of Spirit Weed. In this investigation, convulsions were induced by picrotoxin (4.5 mg/kg, i.p.) and these convulsions were consistently abolished by the intraperitioneal (i.p.) infections of aliquots (3ml each) of a steam distillate extract of Spirit Weed. However, those rats which served as controls as well as those which were injected with aliquots (3 ml each) of the boiled aqueous decoction of Spirit Weed, died after 2 hours of convulsions. Also, the steam distillate extract of Spirit Weed delayed (by 12 + 3 minutes) the onset of convulsions when it was given before picrotoxin (4.5 mg/kg, i.p.). Additionally, the steam distillate extract of Spirit Weed mimicked the anticonvulsant effect of phenobarbitone in the same group of rats. Moreover, the steam distillate extract of Spirit Weed did not produce generalized central nervous sustem depression in conscious rats. Therefore, it is concluded that an ingredient in the steam distillate extract of Spirit Weed has anticonvulsant properties which may be useful in the treatment of some forms of epilepsy. This requires further investigation (AU)

Long-term effects of marihuana smoke on uterine contractility and tumour development in rats

The present investigation considered the role of acute and chronic marihuana smoking, as well as crude extracts of marihuana (ME), on uterine contractions and tumour development. The contractions and the electrical activity were recorded on isolated superfused rats' uteri. Enhanced spontaneous activity and contractile responses were observed following exposure to marihuana smoke. Atropine failed to block contractile responses with ME following chronic smoke exposure. It is suggested that ME contains both contractile and relaxing properties. Chronic exposure to marihuana smoke resulted in appearance of various tumours in 50 percent of experimental animals. This study suggested far-reaching consequences on reproductive activity following chronic use of marihuana (AU)

Contractile response of uterine smooth muscle to acetylcholine and marijuana extract

Marijuana extract (ME) is known to influence smooth muscle activity. This study was designed to investigate the effect of crude ME on rat uterine muscle and to explain the mechanism of action using antagonists such as atropine, ergometrine and propranolol. The contractions and the electrical activity were recorded on isolated superfused rat uteri. It is speculated that ME by its uterine stimulation action compromise uterine blood and may affect oxygen/nutrient transfer. The implication of this to the fetus is discussed. (AU)