Recent Progress of Basic Studies of Natural Products and Their Dental Application.

The present article reviews the research progress of three major polyphenols (tannins, flavonoids and lignin carbohydrate complexes), chromone (backbone structure of flavonoids) and herbal extracts. Chemical modified chromone derivatives showed highly specific toxicity against human oral squamous cell carcinoma cell lines, with much lower toxicity against human oral keratinocytes, as compared with various anticancer drugs. QSAR analysis suggests the possible correlation between their tumor-specificity and three-dimensional molecular shape. Condensed tannins in the tea extracts inactivated the glucosyltransferase enzymes, involved in the biofilm formation. Lignin-carbohydrate complexes (prepared by alkaline extraction and acid-precipitation) and crude alkaline extract of the leaves of Sasa species (SE, available as an over-the-counter drug) showed much higher anti-HIV activity, than tannins, flavonoids and Japanese traditional medicine (Kampo). Long-term treatment with SE and several Kampo medicines showed an anti-inflammatory and anti-oxidant effects in small size of clinical trials. Although the anti-periodontitis activity of synthetic angiotensin II blockers has been suggested in many papers, natural angiotensin II blockers has not yet been tested for their possible anti-periodontitis activity. There should be still many unknown substances that are useful for treating the oral diseases in the natural kingdom.

Use of flowering gene FLOWERING LOCUS T (FT) homologs in the phylogenetic analysis of bambusoid and early diverging grasses.

A nuclear gene, FLOWERING LOCUS T (FT) homolog, was cloned from Phyllostachys meyeri as PmFT. Its putative copy number was estimated as four by Southern blot analysis, and the two copies were completely sequenced. Twenty-seven FT homolog sequences of bambusoid and early diverging grasses comprised 172-bp exons, and 357- to 785-bp introns exhibited 0-58.9% pairwise divergence with six modal levels. Parsimony analyses of the FT homologs rooted at Pharus virescens produced six equally parsimonious trees. In the strict consensus tree, five clades were resolved; they were affected by divergence of the intron region rather than exon region. The basal clade was Puelioideae, followed by Olyreae clade including Oryza sativa. Streptogyneae clade combined the Olyreae clade with terminal sister clades of the Bambuseae, i.e., pantropical bamboos and East Asiatic temperate bamboos. The global topology suggested that FT homologs are significant for resolving the tribe level. However, the phylogeny of FT homologs does not resolve monophyly in Bambusoideae because of intercalary positioning by Streptogyneae clade. We discussed the role of FT homologs in controlling the inflorescence architecture and position of Streptogyneae in the bamboo phylogeny.

Genetic profiling of Sasa species by analysis of chloroplast intron between rbcL and ORF106 and partial ORF106 regions.

Kuma-zasa is Japanese folk medicine derived from plants of genus Sasa, family Bambusaceae. Although the plants of origin of Kuma-zasa were reported to be Sasa palmata, S. senanensis, S. yahikoensis, and S. kurilensis, authentication of those plants was difficult because of similarity in morphology. Several methods for the classification of genus Sasa are available, but none involve a genetic approach. Here, we performed the genetic profiling of genus Sasa, including the four species used medicinally. Thirteen sequences were observed in chloroplast DNA intron between rbcL and ORF106 and partial ORF106 regions of 34 specimens of 16 Sasa species and one specimen of Phyllostachys pubescens. We observed differences in alignment in this region among the specimens. The analyzed lengths varied from 759 to 821 bp depending on the specimen. There were nine base substitutions, eight successive thymines or adenines, and one to three repeat units of 31 bp. Moreover, we could not find species-specific alignment: different alignments were observed in specimens of the same species, while the same alignment was observed in specimens of different species. In the phylogenetic tree reconstructed by maximum parsimony analysis, medicinally used species did not form a cluster, although most of them were positioned close to each other. The genetic profiling of Sasa species would be of use in determining the botanical origin of the herbal medicine derived from the leaves of Sasa plants.