Low-density lipoprotein-antioxidant flavonoids and a phenolic ester from Plectranthus hadiensis var. tomentosus

Applied Biological Chemistry

Table 1 Antioxidant activity of compounds 1–8 from PHT

Compounds	LDL oxidation inhibition (IC₅₀, µM)^a	DPPH radical scavenging (EC₅₀, µM)^b
Luteolin 7-O-glucuronide (1)	2.8 ± 0.1	26.2 ± 0.2
Rosmarinic acid (2)	1.5 ± 0.1	19.0 ± 0.7
Chrysosplenol D (3)	2.5 ± 0.1	48.3 ± 0.1
Desacetyl plectranthone (4)	NI	NI
Quercetin 3,7-dimethyl ether (5)	3.8 ± 0.1	31.2 ± 0.1
Casticin (6)	22.8 ± 0.4	> 100
Ayanin (7)	53.7 ± 0.1	> 100
(+)-Plectranthone (8)	NI	NI
BHT	1.9 ± 0.4	> 100
L-Ascorbic acid	60.2 ± 1.3	28.1 ± 0.4

Values indicate mean ± SD
NI not inhibited
^aIC₅₀ values indicate the concentration (µM) of sample that caused 50% inhibition of Cu²⁺-mediated LDL oxidation
^bEC₅₀ values indicate the concentration (µM) of sample that scavenged 50% of the DPPH radical