The Compositae plant, Calendula (C.) officinalis L., which is commonly called "Marigold", is widely cultivated as an ornamental. The flowers of this plant are very important in European and western Asian folk medicines and are used to treat inflammatory conditions of internal organs, gastrointestinal ulcers, and dysmenorrhea and as a diuretic and diaphoretic in convulsions. This natural medicine is also known to be used externally for inflammation of the oral and pharyngeal mucosa, wounds, and burns. As chemical constituents of C. officinalis, some triterpenes, triterpene oligoglycosides, and flavonol glycosides have been obtained from the flowers.
2)In the course of our studies on the bioactive principles of medicinal flowers, 1,3) we found that the methanolic extract and its 1-butanol-soluble fraction from the dried flowers of Egyptian C. officinalis showed inhibitory effects on the increase of serum glucose levels in glucose-loaded mice, gastric emptying, and ethanol-induced gastric lesions. From the 1-butanol-soluble fraction, we have isolated four new triterpene oligoglycosides called calendasaponins A (1), B (2), C (3), and D (4), two new ionone glucosides named officinosides A and B, and two new sesquiterpene glycosides termed officinosides C and D. This paper deals with the structural elucidation of calendasaponins (1-4). In addition, we describe the inhibitory effects of the glycoside fraction and principal saponin constituents on the increase of serum glucose levels in glucose-loaded mice, gastric emptying, and ethanol-and indomethacin-induced gastric lesions.The dried flowers of C. officinalis cultivated in Egypt were extracted with methanol under reflux. The methanol extract was partitioned into an ethyl acetate-water mixture to furnish the ethyl acetate-soluble fraction and water phase. The water phase was further extracted with 1-butanol to give a 1-butanol-soluble fraction (the glycoside fraction) and water-soluble fraction. The methanolic extract was found to exhibit inhibitory activity on the increase of serum glucose levels in glucose-loaded mice after a single oral administration of 1000 mg/kg. In the same bioassay, the 1-butanol-soluble fraction showed potent activity at a lower dose (500 mg/kg), as shown in Table 1. As shown in Table 2, the methanolic extract also inhibited gastric emptying in carboxymethyl cellulose sodium salt (CMC-Na) meal-loaded mice after an oral application (500, 1000 mg/kg). The 1-butanol-soluble fraction showed a potent inhibitory effect on gastric emptying at lower doses (250, 500 mg/kg). Furthermore, these extracts were found to show a potent gastroprotective effect in rats (Table 3). Namely, the methanolic extract inhibited gastric lesions induced by ethanol after an oral application (100, 200 mg/kg) in rats, while the 1-butanol-soluble fraction was found to completely inhibit ethanol-induced gastric lesions at a 100 mg/kg dose. On the other hand, the methanolic extract and 1-butanol-soluble fraction completely inhibited indomethacin-induced gastric lesions. The 1...
