Antibacterial effects of 18 medicinal plants used by the Khyang tribe in Bangladesh

Figures & data

Figure 1. Map of Bandarban district and survey areas (circled).

Table 1. Traditional therapeutic properties of 18 medicinal plants from Bangladesh.

Family, genus species and authority	Voucher no.	Date of collection	Locality	Common name	Part used	Traditional therapeutic use
Apiaceae:
Coriandrum sativum L.	030	14 April 2015	Balaghata	Dhone	Seeds	Gastrointestinal disorders
Brassicaceae:
Brassica alba (L.) Rabenh.	022	13 April 2015	Balaghata	Haludsarisha	Seeds	Viral infections
Lepidium sativum L.	011	20 April 2015	Rowanchari bazar	Halimdana	Seeds	Viral infections
Combretaceae:
Terminalia bellirica (Gaern.) Roxb.	006	19 April 2015	Rowanchari bazar	Bohera	Fruits	Fever, cough, dysentery, diarrhoea
Illiciaceae:
Illicum verum Hook.f.	025	18 April 2015	Rowanchari bazar	ChakroPhool	Fruits	Flatulence
Lamiaceae:
Hyptis suaveolens (L.) Poit.	001	25 April 2015	Rowanchari bazar	Tukma	Seeds	Gonorrhoea, fever, headache,
Mentha arvensis L.	014	26 April 2015	Rowanchari bazar	Pudinapata	Leaves	Diarrhoea, thrush
Ocimum basilicum L.	020	27 April 2015	Rowanchari bazar	Tulshibij	Leaves	Cold, coughs, viral or bacterial infection
Vetiveria zizanioides (L.) Nash	002	09 April 2015	Balaghata	Khoskhos	Roots	Bacterial infection, fever
Lauraceae:
Cinnamomum cassia (L.) J. Presl.	035	18 April 2015	Rowanchari bazar	Toz	Bark	Nausea, vomiting and flatulence
Myristicaceae:
Myristica fragrans Houtt.	063	19 April 2015	Rowanchari bazar	Joyfol biz	Fruits	Fever
Pedaliaceae:
Sesamum indicum L.	021	26 April 2015	Rowanchari bazar	Sadatil	Seeds	Watery discharge from pregnant women
Piperaceae:
Piper nigrum L.	057	20 April 2015	Rowanchari bazar	Sadagulmorich	Fruits	Fever, coughs, diarrhoea and diabetes
Ranunculaceae:
Nigella sativa L.	005	8 April 2015	Balaghata	Kalojira	Seeds	Pain during menstruation, diabetes
Zingiberaceae:
Curcuma caesia Roxb.	042	14 April 2015	Balaghata	Kala haila	Rhizomes	Tonsillitis
Curcuma longa L.	046	12 April 2015	Balaghata	Kalohalud	Rhizomes	Skin infection
Curcuma pseudomontana J. Graham	051	13 April 2015	Balaghata	Pahari Halud	Rhizomes	Cold
Curcuma aeruginosa Roxb.	052	13 April 2015	Balaghata	Kathaliholud	Rhizomes	Diarrhoea

Table 2. Percentage yields (w/w).

		Percentage yield (%)
Family, genus species	Part extracted	Hexane	Ethyl acetate	Ethanol
Apiaceae:
Coriandrum sativum	Seeds	1.8	1.7	3.3
Brassicaceae:
Brassica alba	Seeds	29.6	6.7	2.0
Lepidium sativum	Seeds	16.4	2.9	3.6
Combretaceae:
Terminalia bellirica	Fruits	0.2	0.4	0.1
Illiciaceae:
Illicum verum	Fruits	15.0	5.0	2.0
Lamiaceae:
Hyptis suaveolens	Seeds	10.3	2.3	0.9
Mentha arvensis	Leaves	1.3	1.9	2.9
Ocimum basilicum	Leaves	9.8	1.7	0.5
Vetiveria zizanioides	Roots	0.6	1.7	0.1
Lauraceae:
Cinnamomum cassia	Bark	0.9	1.8	10.8
Myristicaceae:
Myristica fragrans	Fruits	33.9	10.9	3.3
Pedaliaceae:
Sesamum indicum	Seeds	34.9	9.4	0.8
Piperaceae:
Piper nigrum	Fruits	2.4	2.6	2.1
Ranunculaceae:
Nigella sativa	Seeds	29.4	5.5	4.3
Zingiberaceae:
Curcuma caesia	Rhizomes	2.6	2.3	1.2
Curcuma longa	Rhizomes	0.1	1.5	1.2
Curcuma pseudomontana	Rhizomes	0.7	2.6	2.4
Curcuma aeruginosa	Rhizomes	4.9	3.4	0.9
Average yield		10.8	3.6	2.3

Table 3. Minimum inhibitory concentrations (MIC) by broth microdilution assay.

			Mean MIC (µg/mL)^a
Family, genus species	Part extracted	Extract^b	MRSA^c	E.f^c	E.c^c	P.a^c	K.p^c	A.b^c
Apiaceae:
Coriandrum sativum seeds		E	375	375	187.5	187.5	187.5	375
Brassicaceae:
Brassica alba	Seeds	H	375	187.5	750	>1500	375	375
		EA	1500	750	375	>1500	375	375
Combretaceae:
Terminalia bellirica	Fruits	EA	187.5	>1500	187.5	>1500	187.5	375
		E	93.7/187.5^d	375	23.4/750^d	187.5	93.7/750^d	11.7/11.7^d
Illiciaceae:
Illicum verum	Fruits	H	375	750	750	>1500	187.5	375
		EA	>1500	1500	375	>1500	1500	187.5
		E	187.5	187.5	275	>1500	187.5	375
Lamiaceae:
Hyptis suaveolens	Seeds	H	375	187.5	187.5	375	375	375
Mentha arvensis	Leaves	H	24.3/>1500^d	187.5	11.7/375^d	375	187.5	93.7/187.5^d
		EA	375	187.5	187.5	>1500	187.5	187.5
		E	275	187.5	375	>1500	750	375
Ocimum basilicum	Leaves	H	187.5	750	375	>1500	375	1500
Vetiveria zizanioides	Roots	H	375	187.5	187.5	>1500	>1500	750
Lauraceae:
Cinnamomum cassia	Bark	H	46.8/187.5^d	46.8/375^d	46.8/93.8^d	93.8/93.8^d	46.8/375^d	11.7/46.8^d
		EA	375	187.5	750	1500	750	1500
		E	187.5	375	187.5	>1500	187.5	187.5
Myristicaceae:
Myristica fragrans	Fruits	H	187.5	750	375	>1500	375	187.5
		EA	750	187.5	750	>1500	1500	187.5
		E	375	750	750	>1500	1500	750
Pedaliaceae:
Sesamum indicum	Seeds	H	375	375	375	>1500	375	375
Piperaceae:
Piper nigrum	Fruits	H	375	187.5	375	>1500	1500	1500
		EA	375	187.5	1500	>1500	1500	750
Zingiberaceae:
Curcuma longa	Rhizomes	H	750	>1500	375	>1500	375	375
Positive control antibiotics:
Vancomycin		1500/1500		11.7/11.7	n.t.	n.t.	n.t.	n.t.
Rifampicin		n.t.		n.t.	11.7/11.7	11.7/11.7	11.7/11.7	1500/1500

^a Values are given as mean of triplicate. n.t.: not tested.

^b H: hexane; EA: ethyl acetate; E: ethanol. Extracts with MIC > 625 µg/mL for all six bacteria tested are not included in the table (Kuete 2010).

^c MRSA: methicillin-resistant Staphylococcus aureus; E.f: Enterococcus faecalis; E.c: Escherichia coli; P.a: Pseudomonas aeruginosa; K.p: Klebsiella pneumoniae; A.b: Acinetobacter baumannii.

^d Minimum bactericidal concentrations (MBC) were determined for extracts with MIC < 100 µg/mL. Values are given as mean of triplicate.

Table 4. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of three phytoconstituents by broth microdilution assay.

		Mean MIC/MBC (µg/mL)^a
Phytoconstituent	Plant of origin	MRSA^b	E.f^b	E.c^b	P.a^b	K.p^b	A.b^b
Cinnamaldehyde	Cinnamomum cassia	750/1125	11.7/11.7	23.4/23.4	1500/1500	750/1125	1500/1500
Eugenol	Cinnamomum cassia	750/1125	11.7/11.7	11.7/11.7	23.4/23.4	11.7/11.7	1500/1500
	Mentha arvensis
Gallic acid	Terminalia bellirica	750/1500	1500/1500	750/750	750/750	750/750	1500/1500
Positive control antibiotics:
Vancomycin		1500/1500	11.7/11.7	n.t.	n.t.	n.t.	n.t.
Rifampicin		n.t.	n.t.	11.7/11.7	11.7/11.7	11.7/11.7	1500/1500

^a Values are given as mean of triplicate. n.t.: not tested.

^b MRSA: methicillin-resistant Staphylococcus aureus; E.f: Enterococcus faecalis; E.c: Escherichia coli; P.a: Pseudomonas aeruginosa; K.p: Klebsiella pneumoniae; A.b: Acinetobacter baumannii.

Table 5. Time-killing assay of eugenol and cinnamaldehyde against methicillin-resistant Staphylococcus aureus.

	Bacteria count Log10 (CFU/mL)^a
Time (h)	0	1	2	3	4	5
Eugenol (2 × MIC)	6	0	0	0	0	0
Eugenol (4 × MIC)	6	0	0	0	0	0
Cinnamaldehyde (2 × MIC)	6	4.6	4.5	4.0	0	0
Cinnamaldehyde (4 × MIC)	6	0	0	0	0	0
Cefotaxime (1 × MIC)	6	4.7	4.1	4.0	4.0	4.1
Vancomycin (1 × MIC)	6	4.4	3.4	3.6	3.1	3.1

^a Values are given as mean of triplicate.

Table 6. Fractional inhibitory concentration index (FICI) of different combination of hexane extract of Cinnamomum cassia, cinnamaldehyde or eugenol, and antibiotics against methicillin-resistant Staphylococcus aureus.

	FICI^a	Effect^b
Extract^c
Cefotaxime	>4.2	Antagonistic
Vancomycin	>4.2	Antagonistic
Cinnamaldehyde
Cefotaxime	2.2	Indifferent
Vancomycin	0.3	Synergistic
Eugenol
Cefotaxime	>4.2	Antagonistic
Vancomycin	>4.2	Antagonistic

^a Values are given as mean of triplicate.

^b FICI: ≤0.5 synergistic, 0.5–1 additive, 1–4 indifferent; ≥4 antagonistic (Schelz et al. 2006).

^c Hexane extract of bark of Cinnamomum cassia.

Kuete V. 2010. Potential of Cameroonian plants and derived products against microbial infections: a review. Planta Med. 76:1479–1491.

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Schelz Z, Molnar J, Hohmann J. 2006. Antimicrobial and antiplasmid activities of essential oils. Fitoterapia. 77:279–285.

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