Table 3.

Naphthohydroquinones (8–12) isolated from Pentas species.

Isolated compound	Structure	Species	Extract/Organ	Refs.
Busseihydroquinone A 8 R1 = H, R2 = OH, R3 = OCH3, R4 = CH3, R5 = H		P. bussei	Crystallized out as needles from (DCM/MeOH)/Root	[23]
Methyl 8-hydroxy-1,4,6,7-tetramethoxy-2-naphthoate 9 R1 = CH3, R2 = OH, R3 = OCH3, R4 = CH3, R5 = H			Hexane/Root	[25]
Parvinaphthols A 10 R1 = H, R2 = OH, R3 = OH, R4 = CH3, R5 = H		P. parvifolia	(DCM/MeOH)/Root	[24]
Parvinaphthols B 11 R1 = H, R2 = H, R3 = H, R4 = H, R5 = OH
1,4,5-Trihydroxy-3-methoxy-6-(3,7,11,15,19-pentamethyleicosa-2,6,10,14,18-pentaenyl)naphthalene 12			EtOAc/Root	[25]