Antibiofilm and quorum sensing inhibitory activity of Achyranthes aspera on cariogenic Streptococcus mutans: An in vitro and in silico study

Figures & data

Table 1. The growth and biofilm inhibitory activity of A. aspera extracts on cariogenic isolate S. mutans.

		Growth and biofilm inhibitory activity of the extracts
	Nature of	Growth inhibition	Biofilm inhibition activity
S. No	the extract	(zone of inhibition diameter, mm)	Mean OD	SD	CV	Percentage of reduction
1	Control	–	1.739	–	–	–
2	Aqueous	13 ± 0	1.041	0.09	8.64	42.3
3	Benzene	18 ± 3	0.518	0.44	84.9	74.1
4	Petroleum ether	16 ± 2	0.711	0.048	6.74	62.3
5	Methanol	23 ± 2	0.175	0.077	44.1	94.9

OD: optical density; SD: standard deviation; CV: co-efficient of variation.

Figure 1. GC–MS chromatogram of anticariogenic methanol extract of A. aspera showing the compounds and their percentage of abundance (within parentheses). (1) 3-hydroxyoxolan-2-one (0.19); (2) oxane-2,6-dione (0.91); (3) 1,4-dimethylpiperazine (1.82); (4) methylglyoxal (0.98); (5) 4-hydroxy-2,5-dimethylfuran-3-one (1.39); (6) 4-methoxyphenol (0.32); (7) N-(3-methylbutyl)-N-pentylnitrous amide (0.35); (8) 3,3-diethyl-1-methyldiaziridine (0.28); (9) N-methyl-N-propan-2-ylnitrous amide (1.15); (10) 2,3,4,5-tetrahydroxypentanal (1.20); (11) 3,5-dihydroxy-6-methyl-2,3-dihydropyran-4-one (9.80); (12) 4-hydroxyoxolan-2-one (0.48); (13) 3,5-dihydroxy-2-methylpyran-4-one (0.21); (14) benzene-1,2-diol (0.11); (15) 1-(furan-2-yl)ethane-1,2-diol (0.78); (16) 5-(hydroxymethyl)furan-2-carbaldehyde (60.33); (17) nonanoic acid (0.18); (18) 4-ethenyl-2-methoxyphenol (1.1); (19) hexyl 3-oxobutanoate (0.11); (20) 2,6-dimethoxyphenol (0.05); (21) 3-hydroxy-4-methoxybenzaldehyde (0.02); (22) (2R,3R,4S,5S,6R)-2-[(2S,3S,4S,5R)-3,4-dihydroxy-2,5-bis(hydroxymethyl) oxolan-2-yl] oxy-6-(hydroxymethyl) oxane-3,4,5-triol (0.02); (23) 2-(hydroxymethyl)-2-nitropropane-1,3-diol (0.03); (24) 2-hydroxy-5-methylbenzene-1,3-dicarbaldehyde (0.01); (25) 1-methoxy-3,5-dimethylbenzene (0.12); (26) (1R,2S,3S,4R,5R)-6,8-dioxabicyclo[3.2.1]octane-2,3,4-triol (0.12); (27) 1-(3,5-dimethoxyphenyl)ethanone (0.10); (28) oxan-4-ol (0.02); (29) 5,5-diethyl-1-methyl-1,3-diazinane-2,4,6-trione (0.11); (30) 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanone (0.03); (31) 4-[(E)-3-hydroxyprop-1-enyl]-2-methoxyphenol (0.05); (32) tetradecanoic acid (0.01); (33) 1-(2,6-dihydroxy-4-methoxyphenyl)butan-1-one (0.01); (34) 3-methyl-1-(4-phenylbenzoyl)-2-propan-2-ylimidazolidin-4-one (0.07); (35) 1-ethyl-2,3,4,5,6-pentamethylbenzene (0.03); (36) ethyl hexadecanoate (0.03); (37) (E)-3-(4-hydroxy-3,5-dimethoxyphenyl) prop-2-enal (0.01); (38) 2-hydroxy-4-methoxy-3,5,6-trimethylbenzoic acid (0.03); (39) henicosan-11-ylbenzene (0.04); (40) 2,7-diphenyl-1H-indole (0.09); (41) 2-[2-[(E)-2-[4-(dimethylamino)phenyl]ethenyl]-6-phenylpyran-4-ylidene]propanedinitrile (0.10); (42) (3S,10S,13R,14R,17R)-17-[(2R,5S)-5,6-dimethylheptan-2-yl]-10,13-dimethyl-2,3,4,7,11,12,14,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-3-ol (0.03); (43) 4,7-dimethoxy-1,1,4a-trimethyl-8-propan-2-yl-10,10a-dihydro-9H-phenanthren-2-one (0.12); (44) 1-chloroicosane (0.08); (45) 3-(4-chlorophenyl)-1,2,3,4-tetrahydropyrido[1,2-a]benzimidazole-1,2-dicarboxylic acid (0.06); (46) (E)-3,5-bis(4-hydroxyphenyl)pent-4-ene-1,2-diol (0.04); (47) tetratetracontane (0.02); (48) 2,6-ditert-butyl-4-diazoniophenolate (0.04); (49) (2R,3R,11bS)-2-[(6,7-dimethoxy-3,4-dihydroisoquinolin-1-yl)methyl]-3-ethyl-9,10-dimethoxy-2,3,4,6,7,11b-hexahydro-1H-benzo[a]quinolizine (0.04); (50) 9-dodecyl-1,2,3,4,4a,5,6,7,8,8a,9,9a,10,10a-tetradecahydroanthracene (0.02); (51) 2-prop-1-en-2-ylpyrazine (0.05); (52) 7-amino-4-chloro-3-(cyclohexylmethoxy)isochromen-1-one (0.06); (53) (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-3a-(hydroxymethyl)-5a,5b,8,8,11a-pentamethyl-1-prop-1-en-2-yl-1,2,3,4,5,6,7,7a,9,10,11,11b,12,13,13a,13b-hexadecahydrocyclopenta[a]chrysen-9-ol (0.05); (54) hexacosane (0.05); (55) 4,4,6a,6b,8a,11,11,14b-octamethyl-1,2,4a,5,6,6a,7,8,9,10,12,12a,14,14a-tetradecahydropicene-3,13-dione (0.05); (56) (4,5-dimethyl-7a-prop-1-en-2-yl-2,3,3a,5,6,7-hexahydro-1H-inden-4-yl)methanol (0.04).

Figure 2. Streptococcus mutans glucansucrase (PDB:3AIC) superimposed structure with A. aspera natural ligand phytochemicals Betulin (2a); (2R,3R,11bS)-2-[(6,7-dimethoxy-3,4-dihydroisoquinolin-1-yl)methyl]-3-ethyl-9,10-dimethoxy-2,3,4,6,7, 11b-hexahydro-1H-benzo[a]quinolizine (2b); 1,4-dimethylpiperazine (2c); 2R,3R,4S,5S,6R)-2-[(2S,3S,4S,5R)-3,4-dihydroxy-2,5-bis(hydroxymethyl)oxolan-2-yl]oxy-6-(hydroxymethyl)oxane-3,4,5-triol (2d); 2,3,4,5-tetrahydroxypentanal (2e); 3,5-dihydroxy-2-methylpyran-4-one (2f); 2-hydroxy-5-methylbenzene-1,3-dicarbaldehyde (2g) as well as 1-(4-hydroxy-3,5-dimethoxyphenyl)ethenone (2h). Molecular docking superimposed structures of Streptococcus OmpR subfamily response regulator (1NXO) with A. aspera phytochemical natural ligands (3S,10S,13R,14R,17R)-17-[(2R,5S)-5,6-dimethylheptan-2-yl]-10,13-dimethyl-2,3,4,7,11,12,14,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-3-ol (3a); 3-(4-chlorophenyl)-1,2,3,4-tetrahydropyrido[1,2-a]benzimidazole-1,2-dicarboxylic acid (3b); 3,5-dihydroxy-6-methyl-2,3-dihydropyran-4-one (3c); 1-methoxy-3,5-dimethylbenzene (3d); 4,7-dimethoxy-1,1,4a-trimethyl-8-propan-2-yl-10,10a-dihydro-9H-phenanthren-2-one (3e); 5-(hydroxymethyl)furan-2-carbaldehyde (3f); 3-methyl-1-(4-phenylbenzoyl)-2-propan-2-ylimidazolidin-4-one (3g); and 4-hydroxy-2,5-dimethylfuran-3-one (3h).

Table 2. Achyranthes aspera phytochemical natural ligands as well as the antibiotic triclosan docking scores with the active site of S. mutans and S. aureus QS regulators and their predicted bioactivity.

		Docking energy
Compound name	Pub Chem CID	3AIC	1NXO	miLogP	TPSA	N atoms	MW	N violations	N rotb	GPCR	Ion channel modulators	Kinase inhibitors	Nuclear receptor ligand	Protease inhibitors	Enzyme inhibitors
Betulin(1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-3a-(hydroxymethyl)-5a,5b,8,8,11a-pentamethyl-1-prop-1-en-2-yl-1,2,3,4,5,6,7,7a,9,10,11,11b,12,13,13a,13b-hexadecahydrocyclopenta[a]chrysen-9-ol	72326	−8.72	−4.7	7.164	40.456	32	442.728	1	2	0.21	−0.04	−0.41	0.85	0.09	0.51
(2R,3R,11bS)-2-[(6,7-Dimethoxy-3,4-dihydroisoquinolin-1-yl)methyl]-3-ethyl-9,10-dimethoxy-2,3,4,6,7,11b-hexahydro-1H-benzo[a]quinolizine	65033	−8.39	−3.73	4.708	52.538	35	478.633	0	7	0.1	0.02	−0.47	−0.22	0.06	−0.1
1,4-dimethylpiperazine	7818	−6.9	−3.06	0.234	6.476	8	114.192	0	0	−2.85	−2.4	−2.93	−3.44	−3.12	−2.77
(2R,3R,4S,5S,6R)-2-[(2S,3S,4S,5R)-3,4-Dihydroxy-2,5-bis(hydroxymethyl)oxolan-2-yl]oxy-6-(hydroxymethyl)oxane-3,4,5-triol	5988	−6.81	2.5	−3.745	189.526	23	342.297	2	5	0.45	0.16	0.38	−0.12	0.14	0.71
2,3,4,5-Tetrahydroxypentanal	854	−5.45	0.17	−2.216	97.983	10	150.13	0	4	−1.06	−0.35	−1.35	−1.17	−0.71	−0.01
3,5-Dihydroxy-2-methylpyran-4-one	70627	−5.07	−2.15	0.15	70.667	10	142.11	0	0	−2.03	−1.54	−1.87	−1.97	−1.71	−0.59
2-Hydroxy-5-methylbenzene-1,3-dicarbaldehyde	81744	−5	−2.43	1.603	54.37	12	164.16	0	2	−1.05	−0.48	−1	−0.8	−1.28	−0.54
1-(4-Hydroxy-3,5-dimethoxyphenyl)ethanone	17198	−4.88	−2.29	1.191	55.767	14	196.202	0	3	−0.79	−0.37	−0.88	−0.8	−0.98	−0.35
3,5-Dihydroxy-6-methyl-2,3-dihydropyran-4-one	119838	−4.82	−4.5	−0.457	66.761	10	144.126	0	0	−1.59	−0.96	−2.25	−1.6	−1.53	−0.65
4-Ethenyl-2-methoxyphenol	332	−4.79	−2.77	2.128	29.462	11	150.177	0	2	−0.96	−0.28	−1	−0.77	−1.35	−0.46
4-Hydroxyoxolan-2-one	95652	−4.77	−2.51	−1.486	46.533	7	102.089	0	0	−3.17	−2.98	−3.2	−3.23	−2.68	−2.76
5,5-Diethyl-1-methyl-1,3-diazinane-2,4,6-trione	4099	−4.73	−2.95	1.206	66.478	14	198.222	0	2	−0.57	−0.58	−1.1	−1.09	−0.28	−0.35
1-(3,5-Dimethoxyphenyl)ethanone	95997	−4.72	−3.11	1.877	35.539	13	180.203	0	3	−0.93	−0.52	−1.12	−0.94	−1.13	−0.57
4-Hydroxy-3,5-dimethoxybenzaldehyde	8655	−4.59	−2.35	1.083	55.767	13	182.175	0	3	−0.95	−0.36	−0.8	−0.69	−1.27	−0.39
Benzene-1,2-diol	289	−4.5	−2.85	0.993	40.456	8	110.112	0	0	−3.04	−2.51	−3.1	−2.99	−3.24	−2.68
4-Methoxyphenol	9015	−4.48	−0.96	−3.272	167.901	16	260.135	1	2	0.56	1.11	0.5	0.22	0.37	1.1
3-Hydroxy-4-methoxybenzaldehyde	12127	−4.47	−2.56	1.067	46.533	11	152.149	0	2	−1.2	−0.54	−1.13	−0.91	−1.65	−0.64
2,6-Dimethoxyphenol	7041	−4.35	−2.14	1.341	38.696	11	154.165	0	2	−1.04	−0.45	−0.97	−1.1	−1.25	−0.48
5-(Hydroxymethyl)furan-2-carbaldehyde	237332	−4.33	−4.33	0.561	50.439	9	126.111	0	2	−2.71	−2.19	−2.92	−2.73	−3.21	−2.24
N-Methyl-N-propan-2-ylnitrous amide	92271	−4.21	−3.94	0.815	32.673	7	102.137	0	2	−4.03	−3.85	−4.25	−4.66	−3.92	−3.14
Oxan-4-ol	74956	−4.19	−2.45	0.055	29.462	7	102.133	0	0	−3.22	−3.06	−3.34	−2.98	−3.01	−2.82
4-Hydroxy-2,5-dimethylfuran-3-one	19309	−4.19	−4.08	0.551	46.533	9	128.127	0	0	−2.73	−1.8	−3.43	−2.57	−2.78	−1.61
2-Prop-1-en-2-ylpyrazine	62897	−4.11	−2.97	1.202	25.784	9	120.155	0	1	−1.97	−1.08	−2.29	−1.9	−2.17	−1.25
4-Methoxyphenol	9015	−4.04	−2.68	1.515	29.462	9	124.139	0	1	−2.24	−1.57	−2.31	−2.15	−2.51	−1.73
4,4,6a,6b,8a,11,11,14b-Octamethyl-1,2,4a,5,6,6a,7,8,9,10,12,12a,14,14a-tetradecahydropicene-3,13-dione	565780	−3.18	−5.9	6.921	34.142	32	440.712	1	0	0.01	−0.03	−0.58	0.39	−0.11	0.33
(3S,10S,13R,14R,17R)-17-[(2R,5S)-5,6-Dimethylheptan-2-yl]-10,13-dimethyl-2,3,4,7,11,12,14,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-3-ol	22296544	−1.24	−4.63	8.011	20.228	29	398.675	1	5	0.13	−0.01	−0.38	0.85	0.02	0.63
3-(4-Chlorophenyl)-1,2,3,4-tetrahydropyrido[1,2-a]benzimidazole-1,2-dicarboxylic acid	620130	−1.12	−4.58	3.238	92.424	26	370.792	0	3	0.14	−0.13	−0.32	−0.1	−0.03	0.01
1-Methoxy-3,5-dimethylbenzene	70126	−3.69	−4.44	2.819	9.234	10	136.194	0	1	−1.29	−0.8	−1.39	−1.34	−1.53	−0.9
4,7-Dimethoxy-1,1,4a-trimethyl-8-propan-2-yl-10,10a-dihydro-9H-phenanthren-2-one	621440	−2.31	−4.37	4.119	35.539	25	342.479	0	3	0.13	−0.13	−0.43	0.21	−0.15	0.23
2,7-Diphenyl-1H-indole	622897	−2.12	−4.35	5.58	15.791	21	269.347	1	2	0.39	0.15	0.66	0.49	0.07	0.36
3-Methyl-1-(4-phenylbenzoyl)-2-propan-2-ylimidazolidin-4-one	602378	−1.8	−4.17	3.008	40.618	24	322.408	0	3	0.12	0.02	−0.13	−0.36	0.13	0.07
7-Amino-4-chloro-3-(cyclohexylmethoxy)isochromen-1-one	611189	−1.44	−3.93	3.945	65.468	21	307.777	0	3	0.01	−0.08	0.14	−0.04	0.66	0.28
Oxane-2,6-dione	9552079	–	−3.21	0.344	43.376	8	114.1	0	0	−3.04	−2.61	−3.42	−2.87	−2.71	−2.48
(4,5-Dimethyl-7a-prop-1-en-2-yl-2,3,3a,5,6,7-hexahydro-1H-inden-4-yl)methanol	605599	−1.67	−3.92	3.984	20.228	16	222.372	0	2	−0.07	0.07	−0.7	0.28	−0.36	0.29
5-Chloro-2-(2,4-dichlorophenoxy)phenol	5564	−4.69	−6.42	5.133	29.462	17	289.545	1	2	−0.18	−0.18	−0.14	−0.07	−0.43	−0.01