Volume 156, 28 October 2014, Pages 1–8
Research paper
The 15-lipoxygenase inhibitory, antioxidant, antimycobacterial activity and cytotoxicity of fourteen ethnomedicinally used African spices and culinary herbs
Abstract
Ethnopharmacological relevance
Culinary
herbs and spices are widely used ethnomedically across Africa. They are
traditionally employed in the treatment of several ailments including
inflammation disorders, pain alleviation and infectious diseases.
Pharmacological studies are necessary to provide a scientific basis to
substantiate their traditional use and safety. In this study, the
15-lipoxygenase inhibitory, antioxidant, antimycobacterial and the
cytotoxic activities, total phenolic and flavonoid contents of fourteen
edible plants were investigated.
Materials and methods
The
15-lipoxygenase inhibitory activity was evaluated by the ferrous
oxidation-xylenol orange (FOX) assay method. The antioxidant activity
was determined using free-radical scavenging assays. The
antimycobacterial activity was determined by a broth microdilution
method against three species of mycobacteria: Mycobacterium smegmatis, Mycobacterium aurum and Mycobacterium fortuitum
using tetrazolium violet as growth indicator. The cytotoxicity was
assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide (MTT) assay on Vero monkey kidney cells.
Results
All the extracts tested had some 15-lipoxygenase inhibitory activity ranging from 32.9 to 78.64%. Adansonia digitata (fruit) had the highest antioxidant capacity (IC50
values of 8.15 μg/mL and 9.16 μg/mL in the DPPH and ABTS assays
respectively; TEAC of 0.75 in the FRAP assay) along with the highest
amount of total phenolics (237.68 mg GAE/g) and total flavonoids
(16.14 mg E/g). There were good correlations between DPPH and ABTS
values (R2 0.98) and between total phenolics and total flavonoids (R2 0.94). Tamarindus indica had significant antimycobacterial activity against Mycobacterium aurum (MIC 78 μg/mL). As could be expected with edible plants, all the extracts had a relatively low cytotoxicity with LC50 values higher than 102 μg/mL with the exception of the two Aframomum species (33 and 74 μg/mL).
Conclusions
This
study provides scientific support for some of the the traditional uses
and the pharmacological activities of the culinary herbs and spices
investigated. The results suggest that increasing intake of some of
these herbs may be useful in preventing or reducing the progression of
lifestyle-related diseases. The diversity of the pharmacological
activities of the extract from the fruit of Adansonia digitata suggested that this plant might be valuable for application in human and animal health.
Keywords
- Culinary herbs;
- Lipoxygenase;
- Antioxidant;
- Antimycobacterial;
- Cytotoxicity
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