Delivery in vivo of 14-deoxy-11-oxoandrographolide, an antileishmanial agent, by different drug carriers.

An antileishmanial compound, 14-deoxy-11-oxo-andrographolide, a derivative of andrographlide, isolated from the Indian medicinal plant Andrographis paniculata was evaluated for efficacy in free form and in different vesicular delivery modes on hamster model of Leishmaniasis. The subcutaneous injection of free drug reduced the spleen parasite load by 39%, whereas for drug incorporated in liposomes, niosomes and microspheres, reductions in the parasite load were 78%, 91% and 59%, respectively. Moreover, the drug in various delivery modes, particularly in liposomal and niosomal forms, showed no apparent immediate toxicity. Although an inverse linear relationship between the size of carriers and per cent efficacy in reduction of spleen parasite load was established, involvement of other factors such as drug release profiles or rates remains an open question. Because of greater efficacy and lesser toxicity, liposomal, niosomal and possibly microsphere-incorporated 14-deoxy-11-oxo-andrographolide might have clinical application to combat visceral Leishmaniasis.

Bacopasaponin C: critical evaluation of anti-leishmanial properties in various delivery modes.

Bacopasaponin C, an indigenous glycoside, was isolated from Indian medicinal plant Bacopa monniera (b. brahmi) and was tested for antileishmanial properties both in free and in various delivery modes, e.g., niosomes, microspheres, and nanoparticles that are used now as alternatives to more commonly used liposomes. The different vesicles were prepared by published protocols. The percent intercalation of Bacopasaponin C in liposomes, niosomes, and micropspheres determined at its absorption maximal (lambda(max) = 238 nm, epsilon = 8.6 x 10(3) M(-1) x cm(-1)) was found to be 30; for nanoparticles it was 50. At equivalent dose of 1.75 mg/kg body weight, every third day for a total of 6 doses in 15 days, Bacopasaponin C in all the vesicular forms was found to be very active. An inverse linear relationship between the efficacy and the size of the vesicles was established. As analyzed from tissue histology, blood pathology, and specific tests related to normal liver and kidney functions, Bacopasaponin C in each of the four vesicular forms was found to be without any side effects. Thus, because of its indigenous origin and non-toxic nature, Bacopasaponin C could very well be considered for application in the clinic through these alternative delivery modes.

Hepatotoxicity and cholestasis in rats induced by the sesquiterpene, 9-oxo-10,11-dehydroageraphorone, isolated from Eupatorium adenophorum.

Eupatorium adenophorum leaves cause hepatotoxicity and cholestasis in rats. The hepatotoxicant has been characterized as 9-oxo-10,11-dehydroageraphorone (ODA), a cadinene sesquiterpene. Oral administration of ODA, mixed in feed to rats, caused jaundice in 24 h. The liver of the intoxicated animals had focal areas of hepatocellular necrosis, proliferation, and dilation of bile ducts with degenerative changes in the lining epithelium. There was marked increase in the conjugated form of plasma bilirubin and in the activities of the enzymes glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, alkaline phosphatase, lactate dehydrogenase, gamma-glutamyltranspeptidase, glutamate dehydrogenase, and 5'-nucleotidase. The histopathological lesions in liver and biochemical profile of marker enzymes show that ODA induced hepatotoxicity and cholestasis in rats. This is the first report on the toxicity of a cadinene sesquiterpene in rats.

Bacopasaponins E and F: two jujubogenin bisdesmosides from Bacopa monniera.

Two new dammarane-type jujubogenin bisdesmosides, bacopasaponins E and F of biological interest have been isolated from the reputed Indian medicinal plant Bacopa monniera and defined as 3-O-[beta-D-glucopyranosyl(1 --> 3)[alpha-L-arabinofuranosyl(1 --> 2)]alpha-L-arabinopyranosyl]-20-O-(alpha-L-arabinopyranosyl) jujubogenin and 3-O-[beta-D-glucopyranosyl(1 --> 3)[alpha-L-arabinofuranosyl(1 --> 2)]beta-D-glucopyranosyl]-20-O-alpha-L-arabinopyranosyl) jujubogenin respectively by spectroscopic methods and some chemical transformations.

Indolylquinoline derivatives are cytotoxic to Leishmania donovani promastigotes and amastigotes in vitro and are effective in treating murine visceral leishmaniasis.

A wide variety of biologically active compounds contain indole and quinoline nuclei. Some novel indolylquinoline derivatives were synthesized from indole by Friedel-Crafts acylation reaction. Out of the four derivatives tested, 2-(2''-acetamidobenzyl)-3-(3'-indolylquinoline) (C) had no effect on the promastigotes or amastigotes of Leishmania donovani in vitro. The remaining three analogues, 2-(2''-dichloroacetamidobenzyl)-3-(3'-indolylquinoline) (A), 2-(2''-chloroacetamidobenzyl)-3-(3'-indolylquinoline) (B), and 2-(2''-aminobenzyl)-3-(3'-indolylquinoline) (D), inhibited the growth of L. donovani promastigotes in vitro and were cytotoxic to both the promastigote and amastigote forms of the parasite. These three derivatives were also effective in eliminating L. donovani amastigotes from BALB/c mouse peritoneal macrophages in vitro. One indolylquinoline derivative [A] was used to treat established visceral leishmaniasis in BALB/c mice. This compound was significantly more effective than sodium antimony gluconate (SAG) in reducing the splenic parasite load at a much lower concentration (5% of SAG). Our results suggest that indolylquinoline derivatives may be exploited as antileishmanial agents.

Biotransformation of lantadene A (22 beta-angeloyloxy-3-oxoolean-12-en-28-oic acid), the pentacyclic triterpenoid, by Alcaligenes faecalis.

A bacterial strain capable of biotransformation of lantadene A (22 beta-angeloyloxy-3-oxo-olean-12-en-28-oic acid), the pentacyclic hepatotoxin of lantana (Lantana camara var. aculeata) has been isolated from soil using lantadene A as the sole carbon source. The organism is Gram negative, rod shaped, motile, catalase positive and has been identified as Alcaligenes faecalis. The isolate has been found to be specific for lantadene A and did not utilize lantadene B. In studies using sucrose as an additional carbon source, A. faecalis elicited biotransformation of lantadene A to its trans isomer 22 beta-tigloyloxy-3-oxoolean-12-en-28-oic acid, designated as lantadene X and two other minor metabolites which could not be isolated in pure state.

Advances in triterpenoid research, 1990-1994.

Triterpenoids isolated and characterized from various sources are reviewed. The newer spectroscopic techniques used in their structure elucidation, the new skeleta characterized, their total chemical synthesis, and their biosynthesis are discussed. A compilation of the triterpenoids isolated during the period 1990-1994 along with their occurrence, physical data, spectroscopy and X-ray analysis used for their characterization, is included. The biological activities of the triterpenoids are also discussed.

Advances in microbial steroid biotransformation.

Microbial biotransformations of various steroids are reviewed. Developmental studies on hydroxylation, carbon-carbon bond cleavage, enzymatic catalysis in nonaqueous solvents, use of cyclodextrin medium, cell immobilization, and new microbial reactions are highlighted. Various steroid substrates, their metabolites and the microorganisms used for the transformations are compiled covering the literature for the period 1992-1995.

Novel reduction and hydroxylation products formed by Aspergillus fumigatus from Reichstein's substance S.

Fermentation of Reichstein's Substance S with Aspergillus fumigatus (AM-21) under aerobic conditions yielded 17 alpha, 21-dihydroxy-5 alpha-pregn-l-ene-3.20-dione. 17 alpha,20 alpha, 21-trihydroxy-5 alpha-pregn-l-en-3-one. 6 beta,17 alpha, 21-trihydroxypregn-4-en-3,20-dione. 15 beta,17 alpha,21-trihydroxy-5 alpha-pregnane-3,20-dione, and 15 beta, 17 alpha,20 alpha,21-tetrahydroxy-5 alpha-pregn-l-en-3-one. Each microbial metabolite was characterized by spectroscopic methods, including 13C NMR chemical shifts.

Dual inhibition of DNA topoisomerases of Leishmania donovani by novel indolyl quinolines.

omoindolyl)]ty of biologically active compounds contain indole and quinoline nuclei. A one step synthesis of some novel indolyl quinoline analogs e.g. 2-(2"-Dichloro-acetamidobenzyl)-3-(3'-indolyl)-quinoline [1], 2-(2"-Dichloroacetamido-5"-bromobenzyl)-3'-[3'-(5'-bromoindolyl ] -6-bromo quinoline [2], and 2-(2"-acetamido benzyl)-3-(3'-indolyl)-quinoline [3] has been developed under Friedel-Crafts acylation conditions. The compounds inhibit the relaxation and decatenation reactions catalysed by type I and type II DNA topoisomerases of Leishmania donovani. Among the three synthetic indolyl quinolines, the Br-derivative [2] is most active. The results reported here concerning the inhibition of type I and type II DNA topoisomerases indicate that the compounds act as "dual inhibitors" of the enzymes and can be exploited for rational drug design in human leishmaniasis.

Isolation and structure elucidation of three triterpenoid saponins from Acacia auriculiformis.

Three new triterpenoid saponins, proacaciaside-I, proacaciaside-II and acaciamine isolated from the fruits of Acacia auriculiformis, were identified as acacic acid lactone-3-O-beta-D-glucopyranosyl (1 --> 6)-beta-D-glucopyranoside, acacic acid lactone-3-O-alpha-L-arabinopyranosyl (1 --> 2)-beta-D-glucopyranoside and acacic acid lactone-3-O-alpha-L-arabinopyranosyl (1 --> 6)-2-acetamide-2-deoxy-beta-D-glucopyranoside based on their spectral properties and some chemical transformations.

Bacopasaponin D--a pseudojujubogenin glycoside from Bacopa monniera.

A new dammarane-type pseudojujubogenin glycoside, bacopasaponin D, has been isolated from the reputed Indian medicinal plant Bacopa monniera and defined as 3-O-[alpha-L-arabinofuranosyl(I-->2)beta-D-glucopyranosyl]pseudojujub ogenin by spectroscopic methods and some chemical transformations. The 13C signals of the saponin were assigned by DEPT, 1H-1H COSY and HSQC techniques.

Drug delivery system: targeting of pentamidines to specific sites using sugar grafted liposomes.

Different sugar-grafted liposomes were prepared and tested against experimental leishmaniasis in vivo using the classical drug pentamidine isethionate and its methoxy derivative. Both the drugs, when encapsulated in sugar-grafted liposomes were found to be more potent in comparison to normal liposome-encapsulated drug or to the free drug. Moreover, the mannose-grafted liposomes were adjudged to be the best in lowering of spleen parasite load in comparison with those bearing glucose or galactose. When encapsulated in mannose-grafted liposomes the therapeutic efficacy of pentamidine isethionate was found to be better than that of its methoxy derivative, although the latter seemed to be less toxic than the pentamidine isethionate itself.

Dammarane-type triterpenoid saponins from Bacopa monniera.

Three new dammarane-type triterpenoid saponins, bacopasaponins A, B and C, of biological interest have been isolated from the reputed Indian medicinal plant Bacopa monniera and identified as 3-O-alpha-L-arabinopyranosyl-20-O-alpha-L-arabinopyranosyl-+ ++jujubogenin, 3-O-[alpha-L-arabinofuranosyl (1--> 2)alpha-L-arabinopyranosyl]pseudojujubogenin and 3-O-[beta-D-glucopyranosyl (1 -->3)[alpha-L-arabinofuranosyl (1--> 2)]alpha-L-arabinopyranosyl]pseudojujubogenin by spectroscopic methods and some chemical transformations. The hitherto undetermined configurations at C-20 and C-22 of pseudojujubogenin were elucidated by phase-sensitive ROESY, and 1H and 13C signals of the saponins were assigned by DEPT, 1H-1H COSY, HSQC and HMBC techniques.

Triterpenoid saponins from Gymnema sylvestre.

Besides six known gymnemic acids, four new tritepenoid saponins, gymnemasins A, B, C and D, isolated from the leaves of Gymnema sylvestre, were identified as 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucuronopyranosyl]-22-O- tigloyl- gymnemanol, 3-O-[beta-D-glucopyranosyl (1-->3)-beta-D-glucuronopyranosyl]-gymnemanol, 3-O-beta-D-glucuronopyranosyl-22-O-tigloyl-gymnemanol and 3-O-beta-D-glucuronopyranosyl-gymnemanol, respectively. The aglycone, gymnemanol, which is a new compound, was characterized as 3 beta, 16 beta, 22 alpha, 23, 28-pentahydroxyolean-12-ene.

Glycoside-bearing liposomal delivery systems against macrophage-associated disorders involving Mycobacterium leprae and Mycobacterium tuberculosis.

Asiaticoside, a plant glycoside with rhamnose as end sugar and having microbicidal properties was tested against Mycobacterium leprae and Mycobacterium tuberculosis both in vivo and in vitro. As rhamnose is reported to have no tissue specificity, corchorusin D having glucose as end sugar was used for targeting with an equimolar proportion of asiaticoside in liposomal form for testing the drug value. Results showed that liposomal asiaticoside had better microbicidal property against M. leprae and M. tuberculosis when compared to that of free asiaticoside whereas liposomes containing asiaticoside and corchorusin D were found to be equally or more active in comparison to liposomal asiaticoside alone. It is inferred that appropriate glycosides, if used in liposomal form (incorporated or covalently grafted) have enhanced drug efficacy and such glycoside bearing liposomes as targeted delivery systems could be used for chemotherapeutic control of several other diseases.

Rapid micropropagation for Mucuna pruriens f. pruriens L.

A rapid micropropagation system was developed for Mucuna pruriens f. pruriens using explants from 1-week-old aseptically grown seedlings. Multiple shoot regeneration occurred following an initial callus growth on Revised Tobacco (RT) medium supplemented with 2.7 µM NAA and 9.8 µM 2iP. Maximum number of shoot regeneration was achieved only from seedling explant 6 to 7 days old. More than 90% of the regenerated shoots could be rooted on half-strength liquid RT medium supplemented with 2.7 µM NAA. Plantlets readily adopted to greenhouse conditions. This system provides a new tool for micropropagation of Mucuna pruriens f. pruriens, an important medicinal plant.