Uncaria rhynchophylla MIQ

Hirsutine (2-795), which belongs to the corynanthe subgroup of the indole alkaloids, was isolated from the plant Uncaria rhynchophylla MIQ and used for the preparation of the old Chinese folk medicine Kampo [397]. It is of pharmacological interest as it shows a strong inhibitory effect on the influenza A virus (subtype H3N2) with an EC50 = 0.40-0.57 pg ml. which is about 11- to 20-fold higher than that of the clinically used ribavirin [398]. 

Uncaria rhynchophylla Miq. (57). The N-oxide of hirsutine (58) has been found in Uncaria tomentosa DC. (55), and 3-isopaynanthiene (59) has been isolated from Mitragyna speciosa Korth. (58). 

The alkaloids hirsutine (1) and its 3or-epimer dihydrocorynantheine (2a) belong to the corynanthe group of indole alkaloids. They have been isolated from the plant Uncaria rhynchophylla MIQ, which was used for the preparation of the old Chinese folk medicine kampo . Nowadays, 1 and related compounds attract great attention in medicine because of their growth inhibition of the influenza A subtype H3N2 virus. With an EC50 value of 0.40-0.57 ig/mL 1 has shown itself to be 10-20 times more active than the clinically used drug ribavirine (3).1,2 Furthermore, 1 is known for its antihypertensive and antiarrhythmic activity.3... 

Oxindole and indole alkaloids corynoxeine, hirsutine, and hirsuteine from uncaria Uncaria rhynchophylla Miq.) as the main compounds of the extract destabilize the formation of Ap aggregates [185]. They also have a neuropro-tective effect and inhibit glutamate-induced neurotoxicity in the cells of the cerebellum [186]. 

Hsieh C-L, Tang N-Y, Chiang S-Y, Hsieh C-T, Lin J-G (1999) Anticonvulsive and free radical scavenging actions of two herbs, Uncaria rhynchophylla (Miq) Jack and Gastrodia data Bl., in kainic acid-treated rats. Life Sci 65 2071-2082. doi 10.1016/S0024-3205(99) 00473-7... 

Aimi N, Shito T, Fukushima K, Itai Y, Aoyama C, Kunisawa K, Sakai S, Haginiwa J, Yamasaki K 1982 Studies on plants containing indole alkaloid glycosides and other constituents of the leaves of Uncaria rhynchophylla Miq. Chem Pharm Bull 30 4046 - 4051... 

Haginiwa J, Sakai S, Aimi N, Yamanaka E, Shinma N 1973 Studies of plants containing indole alkaloids. (2) On the alkaloids of Uncaria rhynchophylla Miq. Yakugaku Zasshi 93 448-452... 

Uncaria hirsuta Havil U. rhynchophylla Miq. (Syn. Nauclea sinensis Oliv.) Gou Teng (Gambir) (stem) Rhynchophylline, corynoxeine, iso-rhynchophylline, isocorynoxeine, corynantheine, hirsutine, hirsuteine.33 A sedative, anticonvulsive, lower blood pressure, it has a triphasic effect. Treat childhood epilepsy. 

Nauclea rhynchophylla Miq., N. sinensis Oliv., Uncaria hirsuta Havil, U. rhynchophylla Miq. 

The genus Uncaria Schreb., is now regarded as including the genus Ourouparia Aubl. (frequently misspelled), but Nauclea L., though closely related, is still regarded as distinct. The first chemical examination of a plant in these genera seems to be that of N. rhynchophylla Miq. under the name of 0. rhynchophylla Matsum. (177). Subsequently, the plant has been examined but almost invariably referred to as U. rhynchophylla Miq. 

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