Studies on the Constituents of the Leaves of Morus alba L.

Abstract

The root bark of Morus alba L. has been used as a blood pressure depressant in China and Japan from old times. The constituents of the root bark were well investigated by T. Nomura 1) and H. Hikino's 2) groups and many flavones and their derivatives were isolated as active principles. The leaves of this plant have also been used as a blood pressure depressant, but the constituents of the leaves have not yet been thoroughly investigated. We have investigated the pharmacological activities of the leaves of this plant and found that the butanol extracts of the leaves inhibit the increase of serum cholesterol and prevent atherosclerosis. 3a,b) In order to investigate the relationship of the constituents and the pharmacological activities of the leaves, we have studied the constituents of the butanol extracts of mulberry leaves. In this paper, we report the isolation and structural elucidation of two novel prenylflavanes (1, 2) and a glycoside (3) of 1 along with six known compounds, isoquercitrin (4), 4) astragalin (5), 5) scopolin (6), 6) skimmin (7), 7) roseoside II (8) 8) and benzyl D-glucopyranoside (9), 9) from the leaves of M. alba. The substitution pattern on the benzene rings was investigated by the analysis of heteronuclear multiple bond correlation spectroscopy (HMBC) spectrum of 1. As shown in (Fig. 2). The results of the NOE experiments and the spectral data mentioned above was satisfactorily explained by the structure (1) shown in Fig. 2. Results and DiscussionCompound 2 was obtained as an amorphous powder, [a] D Ϫ1.6°(cϭ1.0, MeOH). Its CI-MS spectrum showed the [MϩH] ϩ ion peak at m/z 341 corresponding to the molecular formula C 21 H 25 O 4 . Comparison of the 1 H-and 13 C-NMR spectra of 2 with those of 1 suggested that compound 2 is an isomer having the same framework as 1 and the structural difference should be the location of a methoxyl group. In the HMBC spectrum of 2, the methoxyl proton signal at d 3.74 showed a cross peak with the carbon signal at d 157.0 (C-7) which exhibited long range couplings with the proton signals at d 3.63-3.74 (H-1Љ) assignable to the methylene protons of a prenyl group. Furthermore, in the difference NOE experiments, irradiation of the methoxyl proton signal produced significant enhancement of the proton signal at d 6.57 due to February 2001 Chem. Pharm. Bull. 49(2) Two novel prenylflavanes (1, 2) and a glycoside (3) of 1 were isolated along with six known compounds, isoquercitrin (4), astragalin (5), scopolin (6), skimmin (7), roseoside II (8) and benzyl D-glucopyranoside (9), from the leaves of Morus alba. The inhibitory activities of compounds 1, 2 and 3 on the oxidation of human low density lipoprotein (LDL) were investigated.

Antioxidant and hepatoprotective activities of Egyptian moraceous plants against carbon tetrachloride-induced oxidative stress and liver damage in rats

“…A piperidine alkaloid (1-deoxynojirimycin) and glycoproteins (Morans A and 20K) were isolated as antidiabetic agents from Morus root bark and/or leaf (Yagi et al, 1976;Hikino et al, 1985;Kim et al, 1999). White mulberry leaf contains triterpenes (lupeol), sterols (β-sitosterol), bioflavonoids (rutin, moracetin, quercetin-3-triglucoside, and isoquercitrin), coumarins, volatile oil, alkaloids, amino acids, and organic acids (Doi et al, 2001). On the other hand, the antioxidant potency of some phenolic compounds (flavonoids, stilbenes, and 2-arylbenzofurans) from Morus alba has been reported (Nomura et al, 1977(Nomura et al, , 1980Fukai & Nomura, 1998;Sharma et al, 2001;Jin et al, 2002;Fukai et al, 2003).…”

Inhibitory Effects of Morus alba on Compound 48/80-Induced Anaphylactic Reactions and Anti-Chicken Gamma Globulin IgE- Mediated Mast Cell Activation

“…The species of Morus have been shown to exhibit anti-HIV, anti-oxidative, anti-hypotensive, and cytotoxic activities. [6][7][8] Plants of this genus are known to be rich in flavonoids, 9,10) a group of chemicals shown to have potent antiviral activities against herpes simplex virus, rhinovirus, human immunodeficiency virus, and various respiratory viruses. [11][12][13] This herb has been long used as an antiphlogistic, diuretic, and expectorant, 14) and also applied for control of inflammation, diabetes, and bronchial asthma.…”

Energy and Nutritional Properties of the White Mulberry (Morus alba L.)

“…The white mulberry contains also high amounts of β-carotene, curcumin, gingerol, galusan epigallocatechins and resveratrol, which are considered as components of antioxidants important in cancer prevention [15]. The mulberry flavonoids (rutin, isoquercitrin, astragalin, quercetin) and anthocyanins-the most important antioxidants, show cytotoxic activity against liver cancer cells in rats, human leukemia and melanoma cells in mice [30][31][32]. The polysaccharides from the roots bark stimulate lymphocyte proliferation and reduce the production of antibodies, which plays a significant role in treatment against allergies and is used in allergic diseases [33].…”