In the course of our studies on the bioactive constituents from Egyptian herbal medicines, we characterized the chemical structures and pharmacological activities of the constituents from several Egyptian herbal medicines, Anastatica hierochuntica, Cyperus longus, and Nigella sativa. 1. Anastatica hierochuntica: The whole plants of A. hierochuntica (Cruciferae), which is a winter annual plant of the Sahara-Arabian deserts, are prescribed in Egyptian folk medicine for fatigue and uterine haemorrhage and are used by women as a charm for child birth. Two novel skeletal benzofuranoflavanones, anastatins A (1) and B (2) and three new neolignans termed hierochins A (3), B (4), and C (5) were isolated from the methanolic extract of this herbal medicine. Their absolute stereostructures were determined on the basis of chemical and physicochemical evidence. The inhibitory effects of anastatins (1, 2) and isolated flavonoids (6-10) on D-galactosamine (D-GalN)-induced cytotoxicity in primary cultured mouse hepatocytes were examined. As a result, hepatoprotective activities of 1 (IC_<50>=20μM) and 2 (17μM) were stronger than those of other flavonoids and commercial silybin (40μM), which is well known to show potent hepatoprotective activity. In addition, we examined inhibitory effects of isolated lignans from A. hierochuntica on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophages. Among them, three neolignans, 12 (IC_<50>=31μM), (+)-dehydrodiconiferyl alcohol (13, 26μM), and (+)-balanophonin (14, 23μM) inhibited NO production and induction of inducible NO synthase (iNOS) without cytotoxic effects in the MTT assay. Furthermore, in order to clarify the structural requirements of flavonoids for inhibitory activities of NO production and antigen-induced degranulation from RBL-2H3 cells, we examined inhibitory effects of 73 flavonoids on NO production and the release of β-hexosaminidase from RBL-2H3 cells and clarified several structural requirements for the activities. 2. Cyperus longus: C. longus (Cyperaceae) is widely distributed in Mediterranean, western and central Europe, tropical Africa, and western and central Asia. The whole plants of C. longus have been used as a diuretic and tonic in Egyptian traditional medicine. From the methanolic extract of this herbal medicine, a new nor-stilbene dimer, longusone A (22), three stilbene dimers, longusols A-C (23-25), and six new sesquiterpenes, cyperusols (26-31), were isolated. In addition, the constituents of C. longus were found to show DPPH radical scavenging activity and inhibitory effects on the release of β -hexosaminidase from RBL-2H3 cells and D-GalN-induced cytotoxicity in primary cultured mouse hepatocytes. 3. Nigella sativa: The seeds of N. sativa (common name "Black Cumin") have been used for foods, spices, and also prescribed in Egyptian folk medicine for asthma, flatulence, polio, kidney stones, and abdominal pain, etc. Two new dolabellane-type diterpene alkaloids 43, 44 were isolated from the methanolic extract of this herbal medicine and found to show potent reduction of triglyceride levels in primary cultured mouse hepatocytes.
