The Chemistry of Eremophila Species. IV. Some Flavonoid Constituents

Abstract

A pigment from Eremophila fraseri F. Muell. has been shown to be 5,3',5'-trihydroxy-3,6,7,4'-tetramethoxyflavone by degradation and synthesis of the 3',5'-dimethyl ether. Pinobanksin and galangin-3-methyl ether have been isolated from E. ramossissima and E. alternifolia.

The genus Eremophila (Scrophulariaceae): an ethnobotanical, biological and phytochemical review

“…The first indication of the presence of unusual diterpenes in Eremophila came with the isolation of eremolactone from E. fraseri and E. freelingii in 1962. [81,82] However, since this time several diterpenes have been isolated and identified. These diterpenes can be categorized as shown in the following ( Table 6).…”

“…The first representative was dimethyl syringaresinol (191) from E. glabra. [81] Other lignans include phillyrin (190) from E. racemosa, a new dihydroxylignan from E. dalyana, (+)epieudesmin (193) and (+)-methylxanthoxylol (194) from E. calorhabdos. [53,74,91] Ursolic acid (164) E. caerulea [14] Oleanolic acid (165) R = b-OH E. caerulea [14] 3-Epi-oleanolic acid (166) R = a-OH E. platycalyx [54] Abdel Nasser Singab et al…”

“…It has been isolated or detected in a number of Eremophila species including E. fraseri, E. leucophylla and E. ramosissima. [14,81] Cyanogenic glucosides, such as the b-glucoside prunasin (199), are less common. Prunasin represents the cyanogenic toxic principle of E. maculata, which has been termed Poison bush because of its toxins.…”

“…[6] Verbascoside isolated so far from certain Eremophila species and which may occur more commonly in other Eremophila species is of some pharmacological interest. It exhibits E. oppositifolia [108] CH3-(CH2)n-COOH Stearic acid (168) n = 16 E. oppositifolia [109] Palmitic acid (169) n = 14 E. oppositifolia [109] n-Hexanoic acid (170) n = 4 E. oppositifolia [109] n-Heptanoic acid (171) n = 5 E. oppositifolia [109] n-Octanoic acid (172) n = 6 E. oppositifolia [109] Linoleic acid (173) E. oppositifolia [109] CH3-(CH2)n-CH = CH-(CH2)7-COOH Oleic acid (174) n = 6 E. oppositifolia [109] Palmitoleic acid (175) n = 5 E. abietina [52] Abdel Nasser Singab et al Eremophila: ethnobotany, biology & chemistry [111] Eugenol methyl ether (177) O O E. longifolia [111] Galangin-3-methyl ether (178) R 1 = OCH3; R2 = H; R3 = H; R4 = H; R5 = OH; R6 = H; R7 = OH E. alternifolia [81] 5,7-Dihydroxy-3-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one (179) R1 = OCH3; R2 = H; R3 = OCH3; R4 = H; R5 = OH; R6 = H; R7 = OH E. clarkei [14] 5,7-Dihydroxy-3,6-dimethoxy-2-(4-methoxyphenyl)-4H-chromen-4-one (180) R1 = OCH3; R2 = H; R3 = OCH3; R4 = H; R5 = OH; R6 = OCH3; R7 = OH E. clarkei [14] 3′,5,5′-Trihydroxy-3,4′,6,7tetramethoxyflavone (181) R 1 = OCH3; R2 = OH; R3 = OCH3; R4 = OH; R5 = OCH3; R6 = OCH3; R7 = OH E. fraseri [14,81] 5,7-Dihydroxy-2-(4-methoxyphenyl)-4Hchromen-4-one (182) R1 = H; R2 = H; R3 = OCH3; R4 = H; R5 = OH; R6 = H; R7 = OH E. inflata [14] 5,6,7-Trihydroxy-2-(4-methoxyphenyl)-4Hchromen-4-one (183) R1 = H; R2 = H; R3 = OCH3; R4 = H; R5 = OH; R6 = OH; R7 = OH E. decipiens [14] 5,7-Dihydroxy-6-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one (184) R1 = H; R2 = H; R3 = OCH3; R4 = H; R5 = OH; R6 = OCH3; R7 = OH E. decipiens [14] 4′,7Dimethoxy-5-hydroxyflavone (185) R 1 = H; R2 = H; R3 = OCH3; R4 = H; R5 = OCH3; R6 = H; R7 = OH E. homoplastica [68] Abdel Nasser Singab et al Eremophila: ethnobotany, biology & chemistry [81] [72] [81] (S)-5,7-Dihydroxy-2-phenylchroman-4-one (187) R1 = H; R2 = H; R3 = OH; R4 = H E. flaccida E. exotrachys [72] [ 72,113] (2R,3R)-5-Hydroxy-2-(4-hydroxyphenyl)-7methoxy-4-oxoc...…”

The crystal and molecular structure of isoeremolactone

“…Jefferies, Knox & Middleton (1962) first isolated this compound from Eremophila fraseri F. Muel., which is a common viscid shrub in the central Murchison district of Western Australia.…”