This research work described in this Ph.D. thesis is divided in to three parts. Part A deals with phytochemical investigations on the air-dried roots of a Mongolan medicinal plant, Ferula monolica Seud, whereas Part B describes the chemistry of the rhizomes of an another Mongolian plant Iris flavissima Pall, Part C of the thesis contains the details of bioactivities of the compounds isolated from the above mentioned Mongolian plants and it is further divided into two sub-arts, Part C-1 explains the inhibitory activity of these compounds against the enzyme a-glucosidase, whereas Part C-II deals with the anti-inflammatory activity of the isoflavones isolated from I. flavissima.
The phytochemical investigations on the air-dried roots of Ferula mongolica resulted in the isolation and characterization of six new (compound 1-6) and seven known compounds. The chemical structures of these compounds were determined by using different spectroscopic techniques. These compounds belong to various structural classes as described below:
Sesquiterpenoid Pyrano-benzophyran Derivative: A new sesquiterpenoid pyrano-benzopyrane derivative, baigene A (1) has been isolated from the air-dried roots of F. mongolica.
Sesquiterpenoid Furo-benzopyrane Derivatives: A new sesquitterpenoid furo-benzophyrane derivative, baigene B (2) and a known (2R*,3S*) baigene B (8) have also been isolated from the roots of F. mongolica.
Sesquiterpenoid Furo-Coumarin Derivatives: Two new members f this class, baigene C (3) and 7’-methoxybaigene C (4) along with two known metabolites, (2R*,3S*) baigene C (9) and mongolin C (11) hve also ben isolated from this plant.
Sesquiterpenoid Coumarin Drivative: A new sesquiterpenoid coumarin, mongolin A (5) has also been isolated from the air-dried roots of F. mongolica.
Sesquiterpenoid Benzovl Derivatives: A new compound mongolin B (6), a synthetically known compound 4’-methoxy-dshamirone (7) along with two known sesquiterpenoid benzoyl derivatives, dshamirone (10) and mongolin D (12) have een isolated from the air-dried roots of F. mongolica.
Sesquiterpene: Guaiol (13) is a know sesquterpene, which was also isolated for the first time from F. Mongolica.
Phytochemical investigations on the air-dried roots of another Mongolian medicinal plant, Iris flavissima have resulted in the isolation and characterization of a new isoflavone, sufiol (14) along with nine known isoflavones, iriskashmirianin (15), irisflorentin (16), 3’-O-methyliriskumaonin (17), 4’-methoxyirilone (18), iriskumaonin (19), irigenin (20), iristectorigenin A (21), dichotomitin (22) and iristectorigenin B (23). A well known triterpene, ursolic acid (24), was also isolatd for the first time from this plant.
Isoflavones: A new isoflavone sufiol (14) and nine known isoflavones 15-23 have been isolated for the first time from the air-dried roots of I. flavissima.
Triterpene: A known triterpene ursolic acid was isolated from the roots of I. flavissima for the first time.
This part of the thesis describes the results of some biological assays on newly isolated compounds. Some of these compounds were found to be active against the enzyme a-glucosidaase, whereas some others exhibited significant anti-inflammatory activity. Part C is therefore further divided in to two parts.
Part C (I); This part contains the detail of the enzyme inhibitory activities of the compounds isolated from the roots of F. mongolica and I. flavissima. The inhibition of the a-glucosidase is an effective mean of controlling the hyperglycaemia and late complications associated with type II diabetes, Compounds 1-4, 6-8 and 10-12 exhibited significant enzyme inhibitory activity, while compounds 15, 17, 21 and 23 wwere found to be moderately active.
Part C (II): The reported antioxidant and associated anti-inflammatory activities of flavonoids derivatives of palnt origin, guided that the isoflavones isolated from the roots of I. flavissima were also subjected to anti-inflammatory activity assay. Some of these compounds exhibited significant anti-inflammatory activities. Part-C-II thus describes the details of the anti-inflammatory assays of these compounds.