Of Hernandia species

IDENTIFICATION AND STRUCTURE ELUCIDATION OF REPRESENTATIVE CONSTITUENTS OF HERNANDIA SPECIES... 

CONSTITUENTS OF HERNANDIA SPECIES WITH REPORTED BIOLOGICAL ACTIVITY... 

N-methyl-actinodaphnine possesses 5-hydroxytryptamine receptor blocking activity and a selective antagonist of cq-adrenoceptors, selective for the a1B. than for the a1A-adrenoceptor subtype (14). What are the activities of N-methyl-actinodaphnine and other aporphines of Illigera and Hernandia species against topoisomerase ... 

The plants of Hernandiaceae comprise about sixty-five species in four generic kinds. The plants of Hernandia ovigera L. are widespread in the tropics and the subtropics. In Japan, these plants grow on the beaches of Okinawa and Ogasawara islands. In the Okinawa region, the plants have been used as therapeutic agents. A number of groups have been involved in the isolation and structure elucidation of aporphine-type and isoquinoline-type alkaloids from these plant materials as well... 

The seeds of Hernandia ovigera (8 kg), which were collected in Okinawa, were crushed into small species. Dried seeds (2 kg) were extracted with MeOH (31 x 3) under reflux. The combined extracts were evaporated under reduced pressure to give a residue (1.09 kg). This residue was treated with petroleum ether to remove soluble materials, which afforded the insoluble materials (518 g). This solid residue was extracted with benzene under reflux. After removal of the solvent under reduced pressure, an oily substance (242 g) was obtained. This oily material was recrystallized from EtOH to afford crude crystals of desoxypodophyllotoxin... 

Table 3. Cytotoxic Effects of Isolates from Hernandia Species Against Selected Human and Murine Cancer Cell Lines b...

Tetradecanoylphorbol 13-acetate (TPA) and other diterpene esters from the plant family Euphorbiaceae are well-known as tumor-promotion agents [85]. Thus, inhibition of the biological effects induced by TPA has been considered as a promising strategy [68]. To date, two short-term cell-based in vitro bioassays using TPA as a tumor-promoter have been developed to evaluate the potential cancer chemopreventive activities of several lignans isolated from Hernandia species, namely, inhibition of Epstein-Barr virus early antigen activation [6] and the inhibition of the transformation of JB6 mouse epidermal cells [7]. 

Table 4. Inhibitory Effects of Isolates From Hernandia Species on the Induced Aggregation of Washed Rabbit Platelets b...

Only three iw-aporphine alkaloids (V.1-V.3) were isolated from the two Hernandia species found in Taiwan, the trunk bark of H. nymphaeifolia (Presl.) Kubitzki (25,34) and the root bark of H. ovigera L. (35,36). Two of them [ovihemangerine (V.2) and oviisocorydine (V.3)], possess cytotoxic activity in vitro against human colon cancer cell lines (25) (Table II). (+ )-Ovigeridimerine (V.l), at 50.0 pM, does not inhibit in vitro the platelet aggregation induced by arachidonic acid, collagen, and PAF (13) and the vasorelaxing effect caused by and norepinephrine (22). 

Isoquinoline alkaloids are formed by the reaction of phenylethylamine and formaldehyde, followed by cyclization (28). Menachery has reviewed the occurrence and properties of this structural type of alkaloids (49). In the Hernandiaceae, only five such alkaloids (XI.1-XI.4 and XII.l) have so far shown restricted occurrence in a few species of Hernandia (Table I). Among them, A-methylcorydaldine (XI.l) showed cytotoxic activity in vitro against P-388, CA-KB-16, CA-A549 cells, and the human colon cancer cell line HT-29 (25) and northalifoline (XI.3) exhibited weak in vitro cytotoxity against CA-A549 cells (26) (Table II). 

The family Hernandiaceae consists of four genera Hernandia, Illigera, Gyrocarpus, and Sparattanthelium, and about 60 species of trees, shrubs, and woody climbers widespread in tropical regions. An example of Hernandiaceae is Hernandia ovigera L., which is grown as a tropical street tree. Hernandiaceae are member of the order Laurales and are known to abound with aporphines and lignans. 

Therefore, secondary metabolites such as isoquinoline alkaloids and lignans, from the remaining unstudied species in the genus Hernandia, seem worthy of more extensive chemical and biological investigation. 

A few alkaloids with pyridine (XIII), proaporphine (XIV), and phenanthrene (XVI) nuclei were also found in the Hernandia, Gyrocarpus, and Illigera species, respectively (Table I). Phenanthrene alkaloids, also known as seco-aporphines, are a very rare type, probably formed biogenetically from an aporphine precursor through the opening of ring B (28). Castedo and Tojo have reviewed their chemistry (50). From the family Hernandiaceae only thaliporphinemethine (XVI.l) was isolated from I. pentaphylla Welw. (51). 

The first example of a naturally occurring isoquinolone was doryanine isolated by Gharbo.et al. (1965) from the Australian sassafras tree Doryphora sassafras, and workers of the same laboratory later isolated doryphomine from the same species (Chen et al. 1974). The authors assumed that isoquinolones may be formed in the plant by oxidation of benzylisoquinolines or similar alkaloids, and this view now appears to be generally accepted (Krane and Shamma 1982). Indirect support for this hypothesis may be the presence of the bisbenzyhsoquinoline alkaloid thali-carpine and its two oxidation products hemandaline and N-methyl-6,7-dimethoxy-l-isoquinolone in Hernandia ovigera (Cava and Bessho 1966). 

---