In vitro biological activities of niloticane, a new bioactive cassane diterpene from the bark of Acacia nilotica subsp. kraussiana

• Published in: Journal of ethnopharmacology 2010-04, Vol.128 (3), p.555-560
• Main Authors: Eldeen, I.M.S., Van Heerden, F.R., Van Staden, J.
• Format: Article
• Language: English
• Subjects: Acacia - chemistry; Acacia nilotica; Acacia nilotica subsp. kraussiana; Acetylcholinesterase; Acetylcholinesterase inhibitory activity; Anti-Bacterial Agents - pharmacology; anti-inflammatory activity; Anti-Inflammatory Agents - pharmacology; Antibacterial activity; Bacillus subtilis; Bacillus subtilis - drug effects; bark; bioactive properties; bioassays; Biological and medical sciences; Biological Assay; Cascara; Cerebral Cortex - drug effects; Cholinesterase Inhibitors - pharmacology; Cyclooxygenase 1 - metabolism; Diterpenes; diterpenoids; enzyme inhibitors; Escherichia coli; Escherichia coli - drug effects; Ethnopharmacology; fractionation; General pharmacology; Gram-negative bacteria; Gram-Negative Bacteria - drug effects; Gram-positive bacteria; Gram-Positive Bacteria - drug effects; herbal medicines; in vitro studies; Inhibition of prostaglandin biosynthesis; inhibitory concentration 50; Klebsiella pneumoniae; Medical sciences; medicinal plants; Medicine, African Traditional; Microbial Sensitivity Tests; minimum inhibitory concentration; niloticane; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; plant extracts; prostaglandin synthase; Staphylococcus aureus
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2010.01.057

Acacia nilotica subsp. kraussiana was reported in African traditional medicine for the treatment of various ailments. Isolation of an active compound in this study from the bark extract may lead to the validation of its efficiency as a traditional crude drug. This study aimed to isolate active compound(s) from an ethyl acetate bark extract of Acacia nilotica subsp. kraussiana and to investigate some of its biological activity. The isolation process was carried out using bioassay-guided fractionation. The isolated compound was tested for antibacterial activity using the micro-dilution assay; anti-inflammatory activity using the COX-1 and COX-2 assays and investigated for inhibitory effect against acetylcholinesterase using the microplate assay. A new bioactive compound was isolated and identified as a cassane diterpene, niloticane. Niloticane showed antibacterial activity against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus with MIC values of 4 and 8 μg/mL, respectively. With Gram-negative bacteria, niloticane showed weak activity. MIC values obtained were 16 and 33 μg/mL against Klebsiella pneumonia and Escherichia coli, respectively. In the cyclooxygenase test, niloticane possessed activity with IC 50 values of 28 and 210 μM against COX-1 and COX-2, respectively. IC 50 values observed with indomethacin (positive control) were 3.6 μM for COX-1 and 189 μM for COX-2. In the acetylcholinesterase test, niloticane showed anti-cholinesterase activity with an IC 50 value of 4 μM. IC 50 values obtained by the galanthamine (positive control) was 2.0 μM. The results obtained support the traditional uses of the bark of Acacia nilotica subsp. kraussiana in African traditional medicine for the treatment of some ailments that relate to microbial diseases, inflammation and central nervous system disorders.