Chemical Constituents of Two Liverworts Metacalypogeia Alternifolia and Chandonanthus Hirtellus

Abstract

A novel linear dihydrodichromene derivative, metacalypogin, was identified from the Taiwanese liverwort Metacalypogeia alternifolia. Together with data from M. cordifolia, the chemical marker of the genus Metacalypogeia is obvious chroman derivatives, which is far different from that of Calypogeia, the other genus in the same family. In addition, two isomeric diterpenoids of cembrane‐type were identified from the Chinese liverwort Chandonanthus hirtellus. The relative stereostructures of the latter two isomers were proved by X‐ray crystallography. Both compounds were unstable in chloroform solution and further oxidized to the corresponding peroxy hemiacetal derivatives.

Volatile Components from Selected Tahitian Liverworts

“…This liverwort produced mainly diterpenoids: Cembranes, fusicoccanes and verticillanes were detected. The genus Chandonanthus is known for the presence of cembrane-type diterpenoids, which are chemical markers of this liverwort [3,4,16,17]. The investigated species produced chandonanthone (7), which was previously detected in the Japanese, Taiwanese and Chinese collections [3,17], and also cembrene (thunbergene) (8) and cembrene A (9).…”

Flexibilins A–C, New Cembrane-Type Diterpenoids from the Formosan Soft Coral, Sinularia flexibilis

“…Our studies of S. flexibilis have led to the isolation of three new cembranes, flexibilins A–C ( 1 – 3 ), along with a known metabolite, (−)-sandensolide ( 4 ), and flexibilin B ( 2 ) displayed a moderate inhibitory effect on the release of elastase by human neutrophils. In addition to marine organisms, cembrane-type diterpenoids are also found in higher plants and bryophytes [34,35,36,37,38,39,40,41,42,43]. However, the carboxylic acid moieties exhibited in cembranes 1 and 2 are rarely found [35,44].…”

Cembrane Diterpenes Chemistry and Biological Properties

“…The lipid extract of the soft coral, Sarcophyton glaucum, was found to contain three cembrane-type diterpenes, sarcophytol A (33), sarcophytol acetate (34), and sarcophytol B (35) [18]. An investigation of the Caribbean octocoral Eunicea tourniforti collected along the southwest coast of Barbados afforded four new cembrane diterpenes (36)(37)(38)(39) [19]. Alcyonols A-C (40)(41)(42) were reported by Zvia Kinamoni and his coworkers from Alcyonium utinumii [20], while gibberosenes B-G (43)(44)(45)(46)(47)(48) were identified from the Formosan soft coral, Sinularia gibberosa [21].…”

“…Cembrane-type diterpenoids, (8E)-4a-acetoxy12a,13a-epoxycembra-1(15),8-diene (107) and 13,18,20-epi-isochandonanthone (108) were isolated from the Tahitian liverwort Chandonanthus hirtellus (Web.) Mitt, while C. hirtellus produced three other analogs (109)(110)(111) [38][39][40].…”

“…Chandonanthus hirtellus 107-111 [38][39][40] Echinodorus macrophyllus 444, 445 [129] Anisomeles indica 342-348 [106][107][108] Cleome spinosa 166-170 [64] Echinodorus grandiflorus 68 [32] Croton gratissimus 638 [182] Croton laevigatus 400-405 [120] Croton oblongifolius 103-105, 520, 554-556 [35,36,157] Greek tobacco 69-102 [33,34] very abundant in tropical reef environments. The abundance and ease of collection of these invertebrates has facilitated an extensive investigation of their secondary metabolism.…”