Adeleke Clement Adebajo

Pharmacological properties of the extract and some isolated compounds of Clausena lansium stem bark: Anti-trichomonal, antidiabetic, anti-inflammatory, hepatoprotective and antioxidant effects

ETHNOPHARMACOLOGICAL RELEVANCE Clausena lansium (Fools Curry Leaf) is used for various ethnomedical conditions in some countries, including bronchitis, malaria, viral hepatitis, acute and chronic gastro-intestinal inflammation, and as a spicy substitute of the popular Curry leaf tree (Murraya koenigii). AIM OF THE STUDY This study was to evaluate the ethnomedical uses of the stem bark in inflammatory conditions, hepatotoxicity and to determine the anti-diabetic and anti-trichomonal properties of the plant. MATERIALS AND METHOD Anti-trichomonal, in vivo and in vitro antidiabetic and insulin stimulating, anti-inflammatory, hepatoprotective and anti-oxidant activities using Trichomonas gallinae, glucose loaded rats and in vitro insulin secreting cell line (INS-1 cell), carrageenin-induced rat paw oedema, CCl(4)-induced hepatotoxicity and DPPH scavenging ability methods respectively for the extracts and some isolates were determined. RESULTS A dichloromethane extract was superior over methanolic extract with respect to an anti-trichomonal activity which was measured after 24 and 48 h. The isolated compounds imperatorin and 3-formylcarbazole had the main anti-trichomonal activity (LC(50)s of 6.0, 3.0 and 3.6, 9.7 microg/mL after 24 and 48 h, respectively). Methanolic extract (100 mg/kg) induced maximum and significant (p<0.05) anti-hyperglycaemic activity of 15.8% at 30 min and a 38.5% increase in plasma insulin at 60 min, compared to control. The increase in plasma insulin after 60 min, compared to 0 min, was 62.0% (p<0.05). The significant 174.6% increase of insulin release from INS-1 cells (in vitro) at 0.1 mg/ml indicates that it mediates its antidiabetic action mainly by stimulating insulin release. Imperatorin and chalepin were the major active constituents increasing in vitro insulin release to 170.3 and 137.9%, respectively. 100 mg/kg of the methanolic extract produced an anti-inflammatory activity after 4 h. A sedative effect was not observed. 100 and 200 mg/kg of methanolic extract administered i.p., reduced CCl4-induced hepatotoxicity firstly by 5.3 and 8.4% reduction in phenobarbitone-sleeping time respectively, secondly by reversing the reduction in serum liver proteins by 7.0-8.8%, serum AST, ALT and ALP activities by 27.7-107.9% and thirdly by diminishing increased values of plasma AST, ALT and ALP activities by 13.2-83.8%. The extract exhibited antioxidant activities. CONCLUSION The hepatoprotective activity of C. lansium is partly due to its anti-oxidant and anti-inflammatory properties and confirms its folkloric use in the treatment of gastro-intestinal inflammation, bronchitis and hepatitis. In addition the use of C. lansium stem bark would be useful in diabetes and trichomoniasis.

Minor furocoumarins of Murraya koenigii.

Xanthotoxin, isobyakangelicol, phellopterin, gosferol, neobyakangelicol, byakangelicol, byakangelicin and isogosferol are reported as minor furocoumarins of Murraya koenigii seeds.

Two carbazole alkaloids from Murraya koenigii

Abstract The non-cyclized possible biogenetic precursors of girinimbine and mahanimbine, 2-hydroxyl-3-methyl-1-(3-methyl-2-butenyl)carbazole (girinimbilol) and 2-hydroxyl-3-methyl-1-(3,7-dimethyl-2,6-octadienyl)carbazole (mahanimbilol) have been isolated from the stem bark of Murraya koenigii. The structures were established by cyclization to dihydrogirinimbine and a new bicyclocarbazole, bicyclomahanimbiline, respectively.

Evaluation of the Ethnomedical Claims of Murraya koenigii.

Abstract Based on sethnomedicine, Murraya koenigii. (L.) Spreng. is used as a stimulant, antidysentery, and for the management of diabetes mellitus. Twelve carbazole alkaloids were isolated from the stem, seed, and leaf of the plant growing in Nigeria and Sri Lanka. The methanol extracts were devoid of hypoglycemic activity, and some isolates decreased insulin secretion when they were subjected to both in vivo. and in vitro. (insulin secretion from INS-1 cells) antidiabetic tests. The cytotoxicity of the leaf and stem methanol extracts determined by the brine shrimp lethality bioassay were LC50 61.5 and 14.5 µg/ml, respectively. These extracts caused CNS depression in albino mice at the dose levels of 25–400 mg/kg. Also, they had an IC50 of 34.0 and 35.0 µg/ml at 24 h, respectively, against trichomonas. These results confirmed the use of the plant as an antidysentery caused by trichomonas but refute the antidiabetic and stimulant ethnomedical claims for the plant. The differences observed in their alkaloidal composition suggested probable influence of geographical location on the elaboration of carbazole alkaloids in the plant and differences in the localization of carbazole alkaloids in the plant parts.

2,7-dihydroxy-3-formyl-1-(3′-methyl-2′-butenyl)carbazole from Clausena lansium

Abstract Clausena lansium root bark contained chalepensin, chalepin, gravelliferone, angustifoline, indizoline and the new carbazole alkaloid, 2,7-dihydroxy-3-formyl-1-(3′-methyl-2′-butenyl)carbazole.

Composition of the leaf volatile oil of Murraya koenigii growing in Nigeria.

ABSTRACT Analyses of essential oil from leaves of Murraya koenigii (L.) Spreng. (Rutaceae) growing in southern Nigeria revealed an oil composition of predominantly sesquiterpenes (89.1%) The main components of the oil were β-caryophyllene (20.5%), bicyclogermacrene (9.9%), α-cadinol (7.3%), caryophyllene epoxide (6.4%), β-selinene (6.2%) and α-humulene (5.0%).

Evaluation of Ethnomedical Claim III: Anti-hyperglycemic activities of Gongronema latifolium root and stem (民族药物需求评估III：Gongronema latifolium根与茎的降糖活性)

The insulinotropic activity of the combined root and stem of Gongronema latifolium (Asclepiadaceae) was evaluated to justify its African ethnomedicinal use in the management of diabetes.

In Vivo Antiplasmodial Potentials of the Combinations of Four Nigerian Antimalarial Plants

Various combinations of Nauclea latifolia root, Artocarpus altilis stem bark, Murraya koenigii leaf and Enantia chlorantha stem bark used in African ethnomedicine as decoctions for malaria and fevers, and combinations with standard drugs, were investigated for antiplasmodial activities using Plasmodium berghei berghei-infected mice. The respective prophylactic and curative ED50 values of 189.4 and 174.5 mg/kg for N. latifolia and chemosuppressive ED50 value of 227.2 mg/kg for A. altilis showed that they were the best antimalarial herbal drugs. A 1.6-fold increase of the survival time given by the negative control was elicited by M. koenigii, thereby confirming its curative activity. Pyrimethamine with an ED50 of 0.5 ± 0.1 mg/kg for the prophylactic, and chloroquine with ED50 = 2.2 ± 0.1 and 2.2 ± 0.0 mg/kg for the chemosuppressive and curative tests, respectively, were significantly (p < 0.05) more active. Co-administrations of N. latifolia with the standard drugs significantly reduced their prophylactic, chemosuppressive and curative actions, possibly increasing the parasites’ resistance. Binary combinations of N. latifolia or M. koenigii with any of the other plants significantly increased the prophylactic and suppressive activities of their individual plants, respectively. Also, E. chlorantha with A. altilis or N. latifolia enhanced their respective prophylactic or curative activities, making these combinations most beneficial against malaria infections. Combinations of three and four extracts gave varied activities. Hence, the results justified the combinations of ethnomedicinal plants in antimalarial herbal remedies and showed the importance of the three in vivo models in establishing antimalarial activity.

Quercetin, a minor constituent of the antihyperglycemic fraction of Bauhinia monandra leaf.

Diabetes mellitus is a metabolic disorder with symptoms of hyperglycemia. It has been estimated that by 2030 there will be over 4.8 million people with diabetes mellitus in Nigeria. Bauhinia monandra Kurz (Fabaceae), known as ‘‘Abafe’’ in the Nigerian Yoruba tribe, is ethnomedically used in Puerto Rico and Nigeria for the management of diabetes. The leaves of B. monandra have been reported to contain b-carotene, fatty acids, quercetin (1), rutin (2; quercetin-3-O-rutinoside), and 3,4¢,5,7-tetrahydroxyflavone. Antidiabetic activities have been reported for stem bark and leaf extracts, as well as the antioxidant constituents of the leaves. A leaf methanolic extract was shown to have antihyperglycemic actions in vivo, whereas its purified subfractions were both hyperglycemic and antihyperglycemic. Rutin, with in vitro insulin inhibitory activity, was the only compound isolated from the most active butanolic fraction and its isolation was given as a confirmation of similar activity for the hyperglycemic subfractions of the butanolic fraction. To explain the insulin-stimulating activities of the other subfractions, in the present study the butanolic fraction was further investigated chromatographically to identify its insulinotropic constituent(s). The detailed analytical methods, including the solvents and materials used, were as described previously. Analytical thin layer chromatography, HPLC, reversephase column chromatography,H-nuclear magnetic resonance (NMR), and C-NMR were performed and positive (Na) and negative (HCOOH) electron spray impact mass spectroscopy (ESIMS) spectra were obtained as described previously. The leaves of Bauhinia monandra were identified and collected in Obafemi Awolowo University (OAU), Ile Ife, Nigeria, in December 2002. The most active antihyperglycemic butanolic fraction was obtained and purified as reported earlier. As reported previously, the BMBu5–10 subfraction (54 mg) yielded 16-mg precipitate and 38-mg filtrate. Further purification of this filtrate using semipreparative HPLC yielded 16.2 mg of a compound identical to the precipitate, which had been characterized as 2 (rutin). Using the same chromatographic procedure, another compound (14.2 mg) was isolated as a minor component of the filtrate. The ultraviolet, infrared, mass spectrometry, and NMR spectra, especially correlations obtained from H-H-homocosy, heteronuclear multiple bond connectivity (HMBC) and heteronuclear multiple quantum connectivity (HMQC) heterocosy spectra, of this minor component were in agreement with that of 1 (quercetin). Quercetin (1) was isolated from the BMBu5-10 subfraction. The composition of this subfraction was therefore determined as 1 (14.2 mg; 26%) and 2 (32.2 mg; 60%). Moderate in vitro insulin-stimulating and significantly high antihyperglycemic activities have been reported for the n-butanolic fraction of B. monandra leaf. Activitydirected chromatographic purification of this fraction gave subfractions BMBuF7 and BMBuF7C, which, at successively lower doses, demonstrated high antihyperglycemic and in vitro insulin-stimulating activities, comparable (P > 0.05) with those of glibenclamide. Correspondence Adeleke C. Adebajo, Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile Ife, Nigeria. Tel.: +234 803 3679 390 Email: caadebajo@yahoo.com Received 21 February 2012; revised 11 June 2012; accepted 23 June 2012. doi: 10.1111/j.1753-0407.2012.00222.x Journal of Diabetes 4 (2012) 439–441

Larvicidal properties of Eugenia uniflora leaves

Eugenia uniflora is used ethnomedicinally in Nigeria for diseases including malaria and in Brazil the leaves are spread on the floor for its insect-repellent activity. Search for plants useful in the control of vector of Dengue fever, necessitated investigation of the activity of E. uniflora leaf against fourth instars larvae of Aedes aegyptii, using bioactivity guided fractionation. Larvicidal activity (LC50 2.74 and 2.18 mg/ml at 24 and 48 h) of the leaf methanolic extract, comparable (p > 0.05) to Endosulphan (LC50 0.93 and 0.90 mg/ml at 24 and 48 h), was concentrated in the nhexane partition fraction (LC50 2.58 and 1.87 mg/ml at 24 and 48 h). Vacuum liquid chromatography of n-hexane fraction gave fifth and sixth bulked fractions with significantly (p 0.05) to that of Endosulphan and better than their mother fractions. The results established the larvicidal activity of E. uniflora leaf and encouraged further development of these fractions as alternative larvicide in the control of Dengue fever, especially among the rural populations of Africa.