title: Antibacterial, antidiarrhoeal, and cytotoxic activities of methanol extract and its fractions of Caesalpinia bonducella (L.) Roxb leaves.
abstract: BACKGROUND
  Caesalpinia bonducella is an important medicinal plant for its traditional uses against different types of diseases. Therefore, the present study investigated the antimicrobial, antidiarrhoeal, and cytotoxic activities of the methanol extract and ethyl acetate, chloroform, and petroleum ether (pet. ether) fractions of C. bonducella leaves.
  
  
  METHODS
  The antibacterial potentialities of methanol extract and its fractions of C. bonducella leaves were investigated by the disc diffusion method against four gram-positive and five gram-negative bacteria at 300, 500 and 800 μg/disc. Kanamycin (30 μg/disc) was used as the standard drug. Antidiarrhoeal activities of leaf extracts were evaluated at two doses (200 and 400 mg/kg) and compared with loperamide in a castor oil-induced diarrhoeal model in rat. The fractions were subjected to a brine shrimp lethality test to evaluate their cytotoxicity.
  
  
  RESULTS
  The methanol extract and other three fractions exhibited better activities at higher concentrations. Amongst, the chloroform fraction showed maximum activity at all three concentrations (300, 500, and 800 μg/disc) against almost all bacteria. S. aureus and P. aeruginosa showed better sensitivities to all extracts at all three concentrations excluding the pet. ether fraction. Bacillus megaterium and Klebsiella spp. were two bacteria amongst nine that showed lowest sensitivity to the extracts. Maximum zone of inhibition (25-mm) was obtained by the methanol extract at an 800 μg/disc concentration against S. aureus. In the antidiarrhoeal test, all fractions exhibited dose-dependent actions, which were statistically significant (p < 0.05). Ethyl acetate fraction exerted maximum inhibition (51.11%) against defecation, whereas 57.75% inhibition was obtained for loperamide. Moderate cytotoxicity was found for the methanol extract and its three fractions compared with the standard drug vincristine sulfate in the brine shrimp bioassay. In the present study, the LC50 values of the methanol crude extract and ethyl acetate, chloroform, pet. ether fractions and vincristine sulfate were 223.87, 281.84, 112.2, 199.53, and 12.59 μg/mL, respectively. Therefore, the ethyl acetate fraction showed maximum cytotoxicity, whereas minimum cytotoxicity was observed for the chloroform fraction.
  
  
  CONCLUSIONS
  The present study revealed that the ethyl acetate fraction of the C. bonducella leaves has significant antidiarrhoeal properties. The methanol extract and other three fractions of the C. bonducella leaves possess potent antibacterial activities along with moderate cytotoxicities that may lead to new drug development.
authors.forename: Muhammad Mutassim
authors.initials: MM
authors.lastname: Billah
authors.forename: Rafikul
authors.initials: R
authors.lastname: Islam
authors.forename: Hajera
authors.initials: H
authors.lastname: Khatun
authors.forename: Shahnaj
authors.initials: S
authors.lastname: Parvin
authors.forename: Ekramul
authors.initials: E
authors.lastname: Islam
authors.forename: Sm Anisul
authors.initials: SA
authors.lastname: Islam
authors.forename: Akbar Ali
authors.initials: AA
authors.lastname: Mia
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000930:Antidiarrheals / Q000494:pharmacology / Q000627:therapeutic use*; D001156:Artemia / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D029911:Caesalpinia; D003672:Defecation / Q000187:drug effects; D003967:Diarrhea / Q000139:chemically induced / Q000188:drug therapy*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D008139:Loperamide / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D018515:Plant Leaves / Q000187:drug effects; D051381:Rats; D020318:Rats, Long-Evans
chemical_list: D000900:Anti-Bacterial Agents; D000930:Antidiarrheals; D010936:Plant Extracts; D008139:Loperamide