Toxicological studies and bioactivity-guided identification of antimicrobially active compounds from crude aqueous stem bark extract of Boswellia dalzielii

Abstract

Objective: The main objective of this study is to isolate, identify, and quantify the active antimicrobial compounds present in the crude aqueous stem bark extract of B. dalzielii using some common pathogenic microorganisms as well as toxicological profile. Material and Methods: Crude aqueous stem bark extract of Boswellia dalzielii (CASEB) was partitioned by preparative thin layer chromatography (PTLC) using chloroform–methanol–water, 8:2:1 (v/v). The resulting bands were extracted using chloroform–methanol (50:50). The extract of each band was evaluated for antimicrobial activity on Streptococcus pyogenes , Staphylococcus aureus , Escherichia coli , Enterococcus faecalis , Klebsiella pneumonia , Pseudomonas aeruginosa , Proteus mirabilis , Salmonella typhi , and Candida albicans by disc diffusion. Compounds in the most antimicrobially bioactive fraction (MAAF) were identified by high performance liquid chromatography (HPLC), Fourier transform infrared spectrophotometry (FT-IR), and gas chromatography-mass spectrometry (GC-MS). Toxicological profile of the CASEB was evaluated by studying its effect in albino Wister rats. Results: PTLC produced five bands/fractions of which the MAAF was identified as RF 2 -fraction being active against all the isolates except E. coli and K. pneumoniae. HPLC of the MAAF revealed seven components; FT-IR revealed 17 functional groups; GC-MS revealed five compounds of which 93.18% are Oleic acid (44.88%), Squalene (34.16%), and n-Hexadecanoic acid (14.14%). The acute toxicity showed LD 50 > 3,000 mg/kg. Sub-chronic toxicity showed that higher doses of the CASEB caused significant changes in liver function indices and a fatty change with lymphocytic infiltration (sign of acute hepatitis) in the liver tissues, but none of these changes were observed in the kidneys. Conclusion: The antimicrobially active compounds in CASEB were Oleic acid, Squalene, and n-Hexadecanoic acid. These can be further purified and used as precursors of new antimicrobial agents for treating infections especially those due to fungi and Pseudomonas spp. that are known to resist wide array of antimicrobial agents. The LD 50 of CASEB is >3,000 mg/kg in rats. However, long-term consumption of CASEB is associated with significant liver damage.

Boswellia dalzielii Methanol Stem Bark Extract Demonstrates Significant Analgesic Activity in Swiss Albino Mice

“…This suggests that the extract could potentially be used in therapeutic applications without causing harmful effects, at least at this dosage. Several previous studies have presented similar conclusions on Boswellia dalzielii, including one that used a dose of 3000 mg/kg of the plant and recorded no signs of toxicity (26,27). The observed behavioural changes, including decreased locomotion and increased sensitivity to external stimuli, suggest that while the extract may not be acutely toxic, it could have some impact on the nervous system or behaviour.…”

Antidiarrheal and Antispasmodic Effects of Ethanolic Stem Bark Extract of ‎Boswellia ‎dalzielii H. in Wistar Rats

“…Ethanol has the ability to provide higher recovery yield of antioxidants, phenolics, flavonoid, tannins and other bioactive contents responsible for the medicinal use of plants in gastrointestinal disorders. Stem bark was selected for the study due to its higher contents of phytochemicals when compared to leaf or root (Dandashire, et al, 2019).…”

Traditional medicinal plants used for treating emerging and re-emerging viral diseases in northern Nigeria

“… Used to treat diarrhea and fever [31] . Bark is used to treat malaria and yellow fever in Africa [99] Induced total inhibition of poliovirus, astrovirus and 75% inhibition of HSV1 and equine HSV [31] The LD 50 of aqueous stem bark extract was > 3000 mg/kg [100] Poliomyelitis, yellow fever Bridelia ferruginea Benth Used to treat diarrhea, fever, headache, stiffness and boils in Africa [ 101 , 102 ] Acute and sub-chronic toxicity study at 5000 mg/kg did not induce any death or significant alteration of biochemical and histological parameters [101] Poliomyelitis Byrsocarpus coccineus Schumach & Thonn. Used to treat measles, jaundice, anemia, and skin disorders [103] Ethanol root extract acute toxicity at 5000 mg/kg and subchronic toxicity at 800 mg/kg did not cause mortality or biochemical and hematological abnormalities [104] Hepatitis, meningitis, lassa fever, yellow fever, smallpox, poliomyelitis Calotropis procera (Aiton) Dryand Used to treat boils, malaria, fever, pain, respiratory disease, cough, skin infection, cold and pneumonia, eczema in Ghana, Nigeria, Burkina Faso, India, Yemen and Saudi Arabia [55] Induced antiviral effect against HIV, white spot syndrome virus and foot and mouth disease virus [55] It is a toxic plant and induced dose dependent toxicity and nephrotoxicity in vivo [55] .…”