Anti-inflammatory and anti-bacterial activity of South African Erythrina species.
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Date
2000
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Abstract
An investigation was undertaken to determine whether Erythrina species indigenous to
South Africa contained the same type of compounds as Erythrina species not found in
South Africa and to determine whether they displayed any anti-inflammatory and antibacterial activity.
Phytochemical analysis was conducted using thin layer chromatography. A great
similarity was found in the leaf profiles of the species being studied. The leaf and bark
extracts of E. caffra and E. lysistemon appear to have similar profiles when viewed
under normal light and ultraviolet light, (254 and 366 nm). These two species have
similar banding patterns when stained with fast blue reagent for flavonoids and
potassium hydroxide reagent for coumarins. The five species that were tested appear
to contain alkaloids, flavonoids, coumarins and triterpenes just like the species not found in South Africa from this genus.
Dried bark and leaves from E. caffra, E. humeana, E. latissima, E. lysistemon and E.
zeyheri were screened for anti-inflammatory and anti-bacterial activity. Ethanol, ethyl
acetate and water extracts were screened for both anti-inflammatory and anti-bacterial
activity. The cyclooxygenase bioassay was used to test for anti-inflammatory activity.
The ethanol and ethyl acetate extracts generally displayed activity while the water
extracts displayed no activity for both the bark and the leaves. The bark generally
displayed more cyclooxygenase inhibitory activity than the leaves. The bark of E. caffra
and E. lysistemon displayed the highest cyclooxygenase inhibitory activity.
The disc diffussion bioassay was used to screen for anti-bacterial activity. Anti-bacterial
activity was only detected in the water extracts of the leaves. The water extracts of the
bark showed very little or no activity. The bark yielded more anti-bacterial activity than
the leaves. Anti-bacterial activity was mainly displayed against Gram positive bacteria.
The bark of E. caffra and E. lysistemon displayed the highest anti-bacterial activity.
On the basis of the screening results it was decided to use bioasssay guided
fractionation in an attempt to isolate putative anti-inflammatory and anti-bacterial
compounds. A hexane extract from the bark of E. lysistemon was prepared and purified
using a range of chromatographic methods. Vacuum liquid chromatography, separation
using a chromatotron, thin layer chromatography and high performance liquid
chromatography were used to isolate anti-inflammatory compound(s). The isolation
proved to be unsuccessful as the pure compound had no cyclooxygenase inhibitory
activity. It was subsequently determined that the compounds were lost during the HPLC procedure.
An ethanolic extract of the bark of E. Iysistemon was purified in an attempt to isolate an
anti-bacterial compound(s). Vacuum liquid chromatography and separation using the chromatotron was used to purify the crude extract. The more sensitive microtitre bioassay was used to test for anti-bacterial activity against S. aureus. The isoflavone, Wighteone was isolated.
Description
Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.
Keywords
Medicinal plants., Materia medica, Vegetable., Erythrina., Theses--Botany.