In the present work, the anticariogenic activities of nine labdane type-diterpenes and four sesquiterpenes were investigated. Among these metabolites, (-)-copalic acid (CA) was the most active compound displaying MIC values very promising (ranging from 2.0 to 6.0 µg/mL) against the main microorganisms responsible for dental caries: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis and Lactobacillus casei. Time kill assays performed with CA against the primary causative agent (S. mutans) revealed that, in the first 12 h, this compound only inhibits the growth of the inoculum (bacteriostatic effect). However, its bactericidal effect is clearly noted thereafter (between 12 and 24 h). Also, CA did not show a synergistic effect when combined with the anticariogenic gold standard (chlorhexidine, CHD) in the checkerboard assays against S. mutans. In conclusion, the results points out CA as an important metabolite in the search for new effective anticariogenic agents.

The antimicrobial activity of four labdane-type diterpenes isolated from the oleoresin of Copaifera langsdorffii as well as of two commercially available diterpenes (sclareol and manool) was investigated against a representative panel of microorganisms responsible for periodontitis. Among all the evaluated compounds, (−)-copalic acid (CA) was the most active, displaying a very promising MIC value (3.1 µg mL−1; 10.2 µM) against the key pathogen (Porphyromonas gingivalis) involved in this infectious disease. Moreover, CA did not exhibit cytotoxicity when tested in human fibroblasts. Time-kill curve assays performed with CA against P. gingivalis revealed that this compound only inhibited the growth of the inoculums in the first 12 h (bacteriostatic effect). However, its bactericidal effect was clearly noted thereafter (between 12 and 24 h). It was also possible to verify an additive effect when CA and chlorhexidine dihydrochloride (CHD, positive control) were associated at their MBC values. The time curve profile resulting from this combination showed that this association needed only six hours for the bactericidal effect to be noted. In summary, CA has shown to be an important metabolite for the control of periodontal diseases. Moreover, the use of standardized extracts based on copaiba oleoresin with high CA contents can be an important strategy in the development of novel oral care products.

Copaifera species (Leguminoseae) are popularly known as "copaiba" or "copaíva". The oleoresins obtained from the trunk of these species have been extensively used in folk medicine and are commercialized in Brazil as crude oil and in several pharmaceutical and cosmetic products. This work reports a complete validated method for the quantification of β-caryophyllene, α-copaene, and α-humulene in distinct copaiba oleoresins available commercially. Thus, essential oil samples (100μL) were dissolved in 20mL of hexanes containing internal standard (1,2,4,5-tetramethylbenzene, 3.0mM) in a 25mL glass flask. A 1μL aliquot was injected into the GC-FID system. A fused-silica capillary column HP-5, coated with 5% phenyl-methylsiloxane was used for this study. The developed method gave a good detection response with linearity in the range of 0.10-18.74mM. Limits of detection and quantitation variety ranged between 0.003 and 0.091mM. β-Caryophyllene, α-copaene, and α-humulene were recovered in a range from 74.71% to 88.31%, displaying RSD lower than 10% and relative errors between -11.69% and -25.30%. Therefore, this method could be considered as an analytical tool for the quality control of different Copaifera oil samples and its products in both cosmetic and pharmaceutical companies.

Many studies have reported that medicinal plant extracts can inhibit oral pathogen growth or adhesion to surfaces and therefore reduce dental caries formation. The addition of these extracts to oral products like mouthwashes and dentifrices is considered an important strategy in caries control. In this sense, we have developed a Mikania glomerata extract with high ent-kaurenoic acid content (KAMg). So, this work describes the preparation of such extract and the development of a validated HPLC-DAD method to determine its ent-kaurenoic acid (KA) content. Herein it is also described the KAMg in vitro antibacterial evaluation against several cariogenic bacteria in comparison with KA and the investigation of further aspects of the KAMg activity. Toxicological aspects of the developed extract were evaluated by assessing its cytotoxicity and genotoxicity. KA and a KA-rich extract like KAMg showed to inhibit the growth of microorganisms responsible for dental caries at relatively low MIC (Minimum inhibitory concentration) values, albeit not as low as the MIC value obtained for chlorhexidine digluconate (CHD), the golden anticariogenic standard approved by the American Dental Association Council on Dental Therapeutics. However, KAMg was more effective to inhibit the formation of a Streptococcus mutans biofilm with four times lower MICB50 (minimum inhibitory concentration that reduces 50% of the biofilm) value as compared with CHD. Taking into account all these data and considering the absence of genotoxic and cytotoxic activity under the tested conditions, it is suggested that KAMg is a natural product to be considered as active ingredient in oral care products.

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