Antioxidant Activities and Phytochemicals of Leaf Extracts from 10 Native Rhododendron Species in Taiwan

Table 1

Antioxidant activities of methanolic extracts from leaves of 10 native Rhododendron species.

Specimens	Yield (wt%)	IC50 (μg/mL)			Reducing; power; (mg CE/g)	Total phenolic  content; (mg GAE/g)
		DPPH radical scavenging	Superoxide radical scavenging	Ferrous ion chelating
R. breviperulatum	18.4	8.8 ± 1.6^CD	24.3 ± 2.4^ABC	665.3 ± 9.8^F	320 ± 18^BC	265 ± 2^B
R. ellipticum	33.4	14.2 ± 0.9^AB	15.7 ± 1.2^CD	1095.9 ± 31.3^B	298 ± 15^BCD	221 ± 16^CD
R.  formosanum	18.2	10.7 ± 1.0^BCD	20.1 ± 1.3^BCD	928.8 ± 38.1^CD	282 ± 5^CDE	222 ± 16^CD
R. kanehirai	22.5	7.7 ± 0.4^D	33.9 ± 2.7^A	429.1 ± 14.8^G	328 ± 8^B	238 ± 5^BC
R. mariesii	18.0	14.7 ± 0.4^A	29.0 ± 2.8^AB	515.3 ± 4.8^G	225 ± 11^F	165 ± 7^E
R. oldhamii	29.1	7.5 ± 0.9^D	19.6 ± 1.0^BCD	714.1 ± 60.0^EF	326 ± 19^B	264 ± 9^B
R. pseudochrysanthum	6.8	7.5 ± 0.7^D	12.4 ± 0.8^D	1344.4 ± 18.5^A	387 ± 9^A	319 ± 17^A
R. rubropilosum var. rubropilosum	11.4	12.1 ± 1.5^ABC	24.5 ± 1.2^ABC	804.9 ± 22.0^DE	263 ± 9^DEF	193 ± 7^DE
R. rubropilosum var. taiwanalpinum	16.7	10.4 ± 1.2^BCD	34.0 ± 1.2^A	774.1 ± 31.9^EF	243 ± 6^EF	198 ± 5^DE
R. simsii	9.2	11.8 ± 1.0^ABC	31.6 ± 2.9^A	961.2 ± 63.3^C	277 ± 15^CDE	219 ± 4^CD
(+)-Catechin	—	2.1 ± 0.3^E	16.6 ± 0.9^CD	>2000	—	—

The results are presented as means ± SD (n =3). Different letters within a column indicate significant difference at the P < 0.05 level according to Scheffe’s test. The reducing power was calculated as (+)-catechin equivalents (CE). The total phenolic content was calculated as gallic acid equivalents (GAE).