Background
Methods
Plant sampling
Extraction
Total phenolic content
Total flavonoid content
Separation and analysis of flavonoids and phenolic acids
Chalcone Synthase (CHS) assay
In vitro evaluation of antioxidant activity
1,1-Diphenyl-2-picrylhydrazyl (DPPH) assay
Ferric Reducing Antioxidant Potential (FRAP) assay
Antibacterial activity
Preparation of plant extracts
Bacterial cultures and growth conditions
Antibacterial activity assay
Minimum Inhibitory Concentration (MIC)
Statistical analysis
Results and discussion
Total flavonoid content and identification of flavonoid compounds
Plant age (month-old) | Plant parts | Total flavonoids | Quercetin | Rutin | Kaempferol | Catechin | Luteolin | Myricetin |
---|---|---|---|---|---|---|---|---|
3 | leaf | 21.8 ± 3.74b
| 2.43 ± 0.69b
| 1.77 ± 0.26c
| 0.71 ± 0.09a
| 5.49 ± 0.45b
| 1.15 ± 0.14a
| ND |
stem | 4.7 ± 0.68e
| 0.12 ± 0.05e
| 0.36 ± 0.07g
| ND | 1.14 ± 0.10h
| ND | ND | |
rhizome | 11.2 ± 1.26d
| 1.63 ± 0.41c
| 0.81 ± 0.09e
| 0.49 ± 0.04b
| 2.69 ± 0.29f
| 0.44 ± 0.03c
| 0.59 ± 0.03c
| |
6 | leaf | 19.1 ± 2.69b
| 2.26 ± 0.52b
| 1.28 ± 0.32d
| 0.51 ± 0.04b
| 4.12 ± 0.21d
| 0.82 ± 0.06b
| 0.25 ± 0.02e
|
stem | 4.2 ± 0.65e
| 0.16 ± 0.05e
| 0.21 ± 0.04h
| ND | 1.34 ± 0.11g
| ND | ND | |
rhizome | 19.6 ± 3.48b
| 2.49 ± 0.33b
| 2.19 ± 0.41b
| 0.68 ± 0.07a
| 4.68 ± 0.27c
| 0.76 ± 0.07b
| 0.97 ± 0.06b
| |
9 | leaf | 15.2 ± 2.68c
| 1.82 ± 0.24c
| 0.66 ± 0.08f
| 0.50 ± 0.03b
| 3.37 ± 0.41e
| 0.45 ± 0.01c
| 0.33 ± 0.01d
|
stem | 4.1 ± 0.66e
| 0.22 ± 0.06d
| 0.24 ± 0.07h
| 0.12 ± 0.01c
| 1.02 ± 0.06i
| ND | 0.11 ± 0.02f
| |
rhizome | 29.7 ± 4.11a
| 3.94 ± 0.81a
| 2.79 ± 0.48a
| 0.72 ± 0.05a
| 6.12 ± 0.32a
| 1.06 ± 0.11a
| 1.19 ± 0.11a
|
Total phenolic content and identification of phenolic acid compounds
Plant age (month-old) | Plant parts | Total phenolics | Gallic acid | Caffeic acid | Ferulic acid | Cinnamic acid |
---|---|---|---|---|---|---|
3 | leaf | 38.4 ± 2.35b
| 11.62 ± 1.50b
| 1.46 ± 0.28b
| 5.46 ± 0.77a
| 1.88 ± 0.27b
|
stem | 5.8 ± 0.37h
| 1.16 ± 0.53f
| 0.24 ± 0.06f
| ND | 0.16 ± 0.06e
| |
rhizome | 19.2 ± 1.42f
| 6.44 ± 0.49e
| 0.79 ± 0.06d
| 1.19 ± 0.26e
| 0.89 ± 0.05d
| |
6 | leaf | 30.4 ± 2.16c
| 9.27 ± 1.03c
| 1.08 ± 0.04c
| 3.66 ± 0.22b
| 1.26 ± 0.31c
|
stem | 5.9 ± 0.33h
| 1.34 ± 0.64f
| 0.20 ± 0.05f
| ND | 0.21 ± 0.05e
| |
rhizome | 26.7 ± 2.83d
| 9.86 ± 0.96c
| 1.73 ± 0.53b
| 2.66 ± 0.17d
| 1.73 ± 0.41b
| |
9 | leaf | 22.4 ± 1.69e
| 7.61 ± 0.86d
| 1.05 ± 0.09c
| 3.14 ± 0.19c
| 1.09 ± 0.22c
|
stem | 6.7 ± 0.52g
| 1.18 ± 0.66f
| 0.34 ± 0.03e
| 0.26 ± 0.09f
| 0.20 ± 0.07e
| |
rhizome | 44.8 ± 3.16a
| 19.76 ± 2.54a
| 2.71 ± 0.79a
| 3.73 ± 0.36b
| 2.61 ± 0.34a
|
The Enzyme Chalcone Synthase (CHS, EC 2.3.1.74) Activity
Antioxidant activity
Plant age (month-old)/positive controls | Plant parts | DPPH free radical scavenging activity (%) | IC50 (μg/mL) | Ferric reducing antioxidant potential (μM of Fe (II)/g) | IC50 (μg/mL) |
---|---|---|---|---|---|
3 | leaf | 57.82 ± 3.29d
| 98.5 ± 4.35d
| 489.4 ± 20.16d
| 119.42 ± 4.55d
|
stem | 15.46 ± 1.15h
| NO | 117.7 ± 6.53i
| NO | |
rhizome | 34.76 ± 3.31g
| 110.9 ± 3.67c
| 254.0 ± 16.42g
| 134.8 ± 5.21c
| |
6 | leaf | 51.66 ± 3.55e
| 121.4 ± 5.16b
| 437.1 ± 18.73e
| 144.6 ± 4.19b
|
stem | 16.37 ± 1.12h
| NO | 113.6 ± 5.68i
| NO | |
rhizome | 59.41 ± 3.68d
| 86.4 ± 4.19e
| 429.0 ± 19.42e
| 99.7 ± 3.55e
| |
9 | leaf | 43.18 ± 2.49f
| 149.7 ± 5.48a
| 377.2 ± 15.27f
| 164.1 ± 4.79a
|
stem | 16.48 ± 1.74h
| NO | 127.2 ± 6.46h
| NO | |
rhizome | 76.42 ± 3.29b
| 55.8 ± 4.26f
| 581.8 ± 22.18b
| 62.4 ± 3.28g
| |
α-tocopherol | 84.19 ± 4.68a
| 44.8 ± 4.33g
| 849.4 ± 24.16a
| 49.1 ± 2.77h
| |
BHT | 70.25 ± 2.69c
| 58.6 ± 4.75f
| 512.1 ± 17.54c
| 67.7 ± 3.86f
|
Antibacterial activity
Bacterial Strains | Inhibition zone (mm) | |||||
---|---|---|---|---|---|---|
Leaf | Stem | Rhizome | Gentamicin | Ciprofloxacin | DMSO:water (1:9 v/v) | |
Staphylococcus aureus
| 8.7 ± 0.291a
| 1.4 ± 0.173d
| 7.3 ± 0.337b
| 6.5 ± 0.277c
| 7.3 ± 0.276b
| NO |
Bacillus subtilis
| 5.1 ± 0.188c
| 1.2 ± 0.229e
| 5.9 ± 0.121a
| 5.6 ± 0.114b
| 4.8 ± 0.129d
| NO |
Listeria monocytogenes
| 1.0 ± 0.164d
| NO | 1.8 ± 0.367c
| 4.0 ± 0.127ab
| 4.2 ± 0.119a
| NO |
Escherichia coli
| 1.5 ± 0.146c
| NO | 3.5 ± 0.322b
| 5.4 ± 0.318a
| 5.5 ± 0.337a
| NO |
Salmonella typhimurium
| 4.1 ± 0.267d
| NO | 5.3 ± 0.379c
| 7.2 ± 0.272a
| 6.8 ± 0.252b
| NO |
Pseudomonas aeruginosa
| 5.6 ± 0.218c
| NO | 7.0 ± 0.381a
| 6.2 ± 0.365b
| 6.7 ± 0.322a
| NO |
Bacterial Strains | Leaf | Stem | Rhizome |
---|---|---|---|
Staphylococcus aureus
| 30.0 | >100 | 40.0 |
Bacillus subtilis
| 80.0 | >100 | 60.0 |
Listeria monocytogenes
| >100 | NO | >100 |
Escherichia coli
| >100 | NO | >100 |
Salmonella typhimurium
| >100 | NO | 50.0 |
Pseudomonas aeruginosa
| 80.0 | NO | 40.0 |