In vitro biological activities of alkaloids from Cryptolepis sanguinolenta.

In our biological screening of higher plants, an aqueous and an 80% EtOH extract from the root bark of Cryptolepis sanguinolenta showed potent antibacterial, anticomplementary, and moderate antiviral activities, but no antifungal effect could be detected. Bioassay-guided fractionation of the 80% EtOH extract led to the isolation of three alkaloids: quindoline (1), hydroxycryptolepine (2), cryptolepine.HCl (3), and the corresponding base cryptolepine (4).

Anti-complementary activity of Crataegus sinaica.

The 80% and 70% acetone extracts from fruits and leaves of Crataegus sinaica Boiss (Rosaceae) and the ethyl acetate-, butanol-, and water-fractions obtained from these initial extracts as well as the isolated compounds, quercetin (1) (1), hyperoside (quercetin 3-O-galactoside) (2) (2), rutin (quercetin 3-O-rutinoside) (3) (2), vitexin (4) (1), rhamnosylvitexin (5) (3), monoacetylrhamnosylvitexin (6) (3), epicatechin (7) (4), procyanidin B-5 (8) (4), proanthocyanidin A-2 (9) (5), procyanidin B-2 (10) (4), and procyanidin C-1 (11) (4), were tested for their influence on the classical (CP) and alternative (AP) pathways of complement-mediated hemolysis. All extracts and fractions showed a strong anti-complementary effect in a dose-dependent way which was more pronounced on the CP than on the AP. The results indicated that the pure proanthocyanidins were active on the CP.

Antiviral activity of Hawaiian medicinal plants against human immunodeficiency Virus Type-1 (HIV-1).

Hawaiian medicinal plants commonly used for the treatment of a variety of infections were screened for antiviral activity against human immunodeficiency virus type 1 (HIV-1). Sixty-one extracts derived from seventeen plants were tested for selective viral growth inhibition using the LAI (HTLV-IIIB) isolate. The greatest degree of antiviral activity was observed with aqueous extracts made from the bark of Eugenia malaccensis (L.

Anti-microbial activity and anti-complement activity of extracts obtained from selected Hawaiian medicinal plants.

Selected plants having a history of use in Polynesian traditional medicine for the treatment of infectious disease were investigated for anti-viral, anti-fungal and anti-bacterial activity in vitro. Extracts from Scaevola sericea, Psychotria hawaiiensis, Pipturus albidus and Eugenia malaccensis showed selective anti-viral activity against Herpes Simplex Virus-1 and 2 and Vesicular Stomatitis Virus. Aleurites moluccana extracts showed anti-bacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, while Pipturus albidus and Eugenia malaccensis extracts showed growth inhibition of Staphylococcus aureus and Streptococcus pyogenes.

Screening of Rwandese plant extracts for their influence on lymphocyte proliferation.

Plants from Rwanda used in traditional medicine have been investigated for their influence on lymphocyte proliferation with and without the presence of the mitogen phytohemagglutinin. Phytolacca dodecandra displayed a significant mitogenic effect. Several plants inhibited the lymphocyte proliferation after prestimulation with the mitogen.

Screening of hundred Rwandese medicinal plants for antimicrobial and antiviral properties.

A series of 100 Rwandese medicinal plants (267 plant extracts), used by traditional healers to treat infections, were screened for antibacterial, antifungal and antiviral properties. The results of the testing showed that 45% were active against Staphylococcus aureus, 2% against Escherichia coli, 16% against Pseudomonas aeruginosa, 7% against Candida albicans, 80% against Microsporum canis and 60% against Trichophyton mentagrophytes. Not less than 27% of the plant species exhibited prominent antiviral properties against one or more test viruses, more specifically 12% against poliomyelitis, 16% against coxsackie, 3% against Semliki forest, 2% against measles and 8% against herpes simplex virus.

In vitro anticomplementary activity of constituents from Morinda morindoides.

In a screening program for complement classical pathway modulation, an 80% MeOH extract of the leaves of Morinda morindoides showed potent dose-dependent anticomplementary activity. Bioassay-guided chromatographic separation of the active constituents led to the isolation of ten flavonoids of which two were aglycones. The compounds were tested in vitro for their putative complement-inhibiting properties on the classical (CP) and the alternative (AP) pathways of the complement system.

Structure-activity relationship of flavonoids with superoxide scavenging activity.

The superoxide scavenging activities of 12 flavonoids were measured. The superoxide anions were generated by a hypoxanthine-xanthine oxidase system and measured by the nitrite method. The results showed that the scavenging ability enhanced with an increasing number of hydroxyl groups in ring B.