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)

Investigation of the anti-inflammatory properties of leaves of Artocarpus altilis (breadfruit)

OBJECTIVE: The leaves of the breadfruit tree (Artocarpus altilis) are used in folklore medicine in the Caribbean to relieve pain and inflammmation. Our objective was to determine whether there is any scientific basis to this folkloric claim. METHODS: An aqueous decoction of breadfruit leaves (BL) was prepared, and tested for anti-inflammatory activity using the "carrageenan induced rat paw oedema" method. Groups of rats were given doses of BL (15, 30 and 60 mg/kg) and saline (control). Additional experiments were done on isolated guinea pig trachea challenged with acetylcholine (Ach), prostaglandin E2 (PGE2), bradykinin and histamine to investigate the mechanism of action of BL. RESULTS: BL at a dose of 60 mg/kg exhibited significant anti-inflammatory activity (p<0.05) from 0.5 to 4 hours. Lower doses of BL (15 and 30 mg/kg) did not produce any significantly different effects from control (p>0.05). BL antagonized the actions of PGE2 and bradykinin on the trachea but not that of Ach or histamine. CONCLUSION: Our findings suggests that an extract of the breadfruit leaves contains one or more compounds with significant anti-inflammatory properties. However, further studies are required to isolate these compounds and to determine their pharmacological profile. (AU)

Lead posisoning in a rural community in Jamaica

OBJECTIVE: A proliferation of "backyard battery repair shops" in Frazer's Content (Red Pond), St Catherine led to a number of cases of lead poisoning in that community. A lead decontamination project was instituted by Blue Cross of Jamaica Environmental Health Foundation in 1994 to address this problem. The aim of the present study was to evaluate the impact of that intervention. METHODS: Questionnaire were developed and filled in during interviews with 214 volunteers in Frazer's Content. Volunteers awareness of the environmental effects of lead and the success of the socioeconomic programmes were assessed. The medical records from five nearby hospitals were also checked for new cases of lead poisoning. In addition, soil and water samples were collected and analyzed by atomic absortion spectrophotometry for levels of lead. RESULTS: The results indicated that knowledge of lead poisoning had increased significantly since 1994. However, there was a marked decrease in entrepeneurial activities. Two new cases of lead posioning were noted. Seven of the soil samples had elevated lead levels (123-317 ppm) but none of the water samples had lead concentration above the critical level (10 hg/l). CONCLUSION: Based on these findings, it would appear that the decontamination and education projects done in 1994 were mostly successful in achieving their objectives. Entrepreneurial initiatives were not sustained.(Au)

Renal toxicity in wistar rats after acute exposure to the herbicide paraquat (gramoxone)

Ingestion of the herbicide paraquat (gramoxone) continues to be a common means of suicide in the Caribbean. Death is usually attributed to pulmonary fibrosis but recent reports suggest that renal toxicity may also contribute to the mortality. To investigate the effect of acute paraquat exposure on kidney function, adult Wistar rats were dosed orally with either paraquat 60 mg/kg or water (control). The rats (n=12) were placed individually in metabolism cages for 24 hr and urine collected. The animals were sacrificed and organs removed for histological examination. The results showed a significant decrease (P<0.05) in creatinine clearance in paraquat-treated rats compared to controls, indicative of renal dysfunction. Histological examination confirmed damage to the proximal and distal convoluted tubules of the kidneys and there was also evidence of lung pathology. The results are discussed in terms of damage to the kidneys by paraquat resulting in a decrease in its rate of excretion from the body. This leads to an accumulation of the herbicide in tissues and consequent exacerbation of the lung toxicity (AU)

An overview of current research on the biological effects of extracts from the unripe ackee (Blighia sapida L.) - abstract

It has been demonstrated that subacute intraperitoneal administration of high doses of the lipid fraction of the unripe ackee resulted in marked neutropaenia, pulmonary toxicity and changes in the blood chemistry in rats. This study has been carried out to further isolate the neutropaenic principle by testing both aqueous and lipid fractions and to see if this effect could be demonstrated in a different animal species. In mice, intraperitoneal administration of aqueous and lipid extracts of the ackee at a dose regimen of 300mg/kg thrice weekly for six weeks showed an initial rise, followed by a lowering of the neutrophil count, red blood cell count, haemoglobin, platelet count, serum albumin and alkaline phosphatase also decreased. It is concluded that in addition to it's hypoglycaemic principle, both aqueous and lipid extracts of unripe ackee, when adminstered separately, have neutropaenic activity. Further research involving characterization and testing is in progress. (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)

Drugs and the blood-brain barrier

This monograph seeks to provide overall information on the role of the blood-brain barrier particularly in relation to entry of various drugs into the Central Nervous System. (AU)

Drugs and the blood-brain barrier

This monograph seeks to provide overall information on the role of the blood-brain barrier particularly in relation to entry of various drugs into the Central Nervous System.

Caffeine inhibits the central hypotensive action of propranolol in rats

Rats anaesthetized with alpha-chloralose were used to investigate the effects of caffeine on the central hypotensive action of d, l-propranolol(=propranolol). In these rats, intracisternal injections of graded doses (1.7 pmol to 13.6 pmol) of propranolol produced dose-dependent falls in mean arterial blood pressure (7 ñ 0.6 mm Hg to 27 ñ 2 mm Hg) which were inhibit by pretreatment with caffeine at a dose (12.9 pmol, intracisternally) that did not alter basal mean arterial blood pressure. The inhibition was reversible and it had an onset and duration of action of about 10 and 50 minutes respectively. It is concluded that caffeine may reduce the hypotensive response of propranolol during antihypertensive therapy with this drug (AU)