Inhibition of nitric oxide production and free radical scavenging activities of four South African medicinal plants

Figures & data

Table 1 The ethnomedicinal uses of the selected plant species in southern Africa, with pain and inflammation being at least one of the indications for therapeutic use

Plant species	Ethnomedicinal uses	References
Artemisia vulgaris	It is traditionally used for irregular or painful menstruation. It is also used to treat flatulence, distension, colic, diarrhoea, constipation, cramps, worm infestation, hysteria, epilepsy, and vomiting	^Citation10
Acokanthera oppositifolia	Decoctions of the leaves and powdered roots are taken orally or used in the form of a snuff to treat headaches and pain, and infusions are used for abdominal pains, convulsions and septicemia	^Citation7
Plantago lanceolata	Used for stopping excessive bleeding and wound healing	^Citation14
Conyza canadensis	Extracts of the plant are used for rheumatism, and for antidiarrheal and anti-hemorrhoidal use. The extracts also have antiviral and antibacterial activities	^Citation11,Citation15,Citation16

Table 2 The antioxidant activity (DPPH radical scavenging activity) of the selected plant species extracted with solvents of varying polarities

Plant species	IC50 (μg/mL)
	Water	Acetone	Ethyl acetate	Chloroform	n-Hexane
Artemisia vulgaris	ND	2.10±0.32	2.20±1.03	1.36±0.14	3.51±1.22
Acokanthera oppositifolia	2.23±0.91	0.54±0.72	1.81±0.94	0.87±0.65	2.42±1.05
Plantago lanceolata	1.81±0.24	2.02±0.96	0.56±0.03	0.41±0.77	0.41±0.1 7
Conyza canadensis	0.56±0.07	0.87±0.44	2.42±0.98	2.23±1.92	2.02±1.90
Vitamin C	0.04±0.09
Quercetin	0.06±0.37

Abbreviation: ND, Not done.

Table 3 Phytochemical analysis of the n-hexane extracts of P. lanceolata indicating the presence or absence of some of the secondary metabolites presumably responsible for bioactivity of the extracts.

Phytochemicals	Extracts
Anthraquinones	Present
Terpenoids	Present
Flavonoids	Present
Saponins	Present
Tannins	Present
Quinones	Not detected
Coumarins	Not detected
Cardiac Glycosides	Present
Phlobatannins	Present
Phenols	Present
Alkaloids	Present

Note: The phytochemicals tested were proven to have significant biological activities elsewhere.³⁸

Table 4 Inhibition of NO production in LPS-activated macrophages RAW 264.7 by extracts of Acokanthera oppositifolia, Plantago lanceolata, Conyza canadensis and Artemisia vulgaris

Plant species	Extracts (µg/mL)	IC50 (µg/mL)	Percentage inhibition of nitric oxide
Water	Acetone	Ethyl acetate	Chloroform	n-Hexane
Acokanthera oppositifolia	100	32.57	ND	86.72±2.25	98.04±1.06	93.27±4.47	86.97±1.97
	30		ND	37.09±2.44	83.97±4.79	50.62±7.76	39.48±1.52
	10		ND	24.31±2.29	37.22±9.25	21.67±1.83	26.88±1.96
2	ND	16.47±0.94	16.96±5.67	10.35±0.0	23.33±0.68
Artemisia vulgaris	100	41.13	68.24±2.6	100±1.95	97.19±2.82	98.29±0.96	49.15±2.56
	30		38.32±1.5	96.21±1.21	85.8±2.69	87.21±2.25	29.02±1.2
	10		24.9±4.68	68.18±3.39	51.84±1.36	53.13±4.5	25.47±1.87
2	17.64±9.9	27.79±2.4	23.5±3.5	18.55±7.12	16.35±2.29
Plantago lanceolata	100	44.05	84.4±3.7	93.76±1.17	87.76±7.71	85.74±2.48	84.46±1.26
	30		37.89±1.7	51.78±1.73	50.68±5.56	44.13±1.34	38.81±2.19
	10		21.43±3.6	29.87±2.99	28.1±4.17	26.88±0.48	25.83±1.04
2	10.66±3.33	21.67±2.01	18.25±1.5	21.67±1.72	18.68±0.78
Conyza canadensis	100	17.69	95.9±2.88	96.88±1.98	96.33±1.17	98.53±0.0	99.20±0.38
	30		53.9±7.04	98.29±1.46	96.94±1.31	97.67±0.57	98.71±0.4
10	31.71±2.26		97.31±1.67	94.31±4.43	80.11±2.64	71.61±0.77
	2	15.5±6	51.60±1.65	53.80±4.08	48.17±0.69	37.58±1.59

Abbreviations: ND, Not done; NO, Nitric oxide; LPS, Lipopolysaccharide.

Table 5 The cytotoxicity, safety profile and percentage cell viability of the extracts of the selected plant species on RAW 264.7 cells in vitro

Plant species	Extracts (µg/mL)	IC50 (µg/mL)	Percentage cell viability
Water	Acetone	Ethyl acetate	Chloroform	n-Hexane
Acokanthera Oppositifolia	100	32.57	ND	67.98±1.53	48.53±2.60	88.10±4.09	93.33±10.60
	30		ND	76.94±4.37	88.06±7.27	96.55±1.37	86.82±8.84
	10		ND	86.32±3,28	99.92±8.76	74.30±3.99	83.72±7.39
2	ND	95.16±2.85	85.78±6.64	80.47±6.68	ND
Artemisia vulgaris	100	41.13	84.46±8.17	10.50±1.96	25.00±2.33	40.35±3.3	59.53±4.16
	30		81.09±5.52	54.96±3.55	73.29±4.17	71.78±0.97	71.63±5.00
	10		70.62±6.87	99.34±10.9	91.01±7.83	79.61±3.82	92.09±6.27
2	74.96±4.61	99.76±6.38	94.88±3.70	88.45±1.99	94.92±10.30
Plantago lanceolata	100	44.05	96.36±19.86	88.80±8.12	94.84±8.60	75.35±2.44	91.90±7.43
	30		94.92±7.20	99.6±10.98	99.16±10.98	91.05±8.87	99.05±10
	10		99.64±11.38	99.57±0.86	99.57±0.86	98.91±4.67	97.93±6.62
2	99.37±1.42	100±10.10	100±4.98	99.31±3.02	83.99±10.53
Conyza canadensis	100	17.69	85.97±9.83	6.20±0.11	5.89±0.05	5.31±0.15	5.70±0.19
	30		99.65±11.29	6.01±0.05	6.67±0.71	54.22±15.80	98.76±2.41
10	99.25±16.16		89.57±7.91	89.96±8.62	77.21±0.33	98.18±0.46
	2	100±1.06	78.84±8.53	94.2±11.07	99.72±7.78	81.20±0.56

van Wyk B, Wink M. Medicinal Plants of the World. Pretoria: Briza Publications; 2004:12.

 Google Scholar

Adedapo AA, Jimoh FO, Afolayan AJ, Masika PJ. Antioxidant activities and phenolic contents of methanol extracts of the stems of Acokanthera oppositilifolia and Adenia gummifera. BMC Complement Altern Med. 2010;8:54. doi:10.1186/1472-6882-8-54

 Web of Science ®Google Scholar

Rosemary G. Medicinal Herbs; a Beginner’s Guide. Storey Publishing; 2012:189–190.

 Google Scholar

Shahkirullah MH, Ahmad MR, Shah I, Ahmad MI, Khan N. Antimicrobial activities of Conyzolide and Conyzoflavone from Conyza canadensis. J Enzyme Inhib Med Chem. 2011;26(4):468–471. doi:10.3109/14756366.2010.52841321054146

 PubMed Web of Science ®Google Scholar

Titanji VPK, Zofou D, Ngemenya MN. The anti-malarial potential of medicinal plants used for the treatment of malaria in Cameroonian folk medicine. Afr J Tradit Complement Altern Med. 2008;5(3):302.20161952

 PubMedGoogle Scholar

Nisar ZS, Naveed M, Zada KA, et al. Phytochemical analysis and antioxidant studies of Conyza bonarensis. Acad J Plant Sci. 2013;6(3):109–112.

 Google Scholar

Miser-Salihoglu E, Akaydin G, Caliskan-Can E, Yardim-Akaydin S. Evaluation of antioxidant activity of various herbal folk medicines. J Nutr Food Sci. 2013;3:222.

 Google Scholar