Meriandra dianthera Aqueous Extract and Its Fraction Prevents Blood Coagulation by Specifically Inhibiting the Intrinsic Coagulation Pathway: An in vitro Study

Background

Currently, cardiovascular disorders are the primary cause of mortality in the world and constitute a serious medical problem. Blood coagulation is an essential process to prevent excessive blood loss through injured blood vessels; however, abnormal blood clotting in the blood vessels can result in fatal cardiovascular disorders. This study investigated the in vitro anticoagulant activity of Meriandra dianthera crude extract and its fractions and their erythrocyte membrane stabilizing activity.

Methods

The plant leaves were extracted by a decoction method and were further fractionated by a liquid–liquid partition with a solvent of crescent polarity. The in vitro anticoagulant activity of the plant extract and its fractions was assessed by PT and APTT assays, while the membrane stabilizing activity was determined through hypotonic induced hemolysis.

Results

The crude aqueous leaf extract of Meriandra dianthera significantly (P < 0.001) prolonged the intrinsic clotting pathway measured by APTT by specifically acting on the intrinsic coagulation pathway. By using liquid–liquid fractionation, the residual aqueous fraction was identified as the fraction responsible for the anticoagulant activity of the crude extract as it significantly (P<0.001) prolonged APTT while the other fractions failed. Both the crude extract and its aqueous residue fraction did not affect the extrinsic coagulation pathway measured by PT. In the membrane stabilizing assay, crude extract and aqueous residue fraction showed the highest membrane stabilizing activity.

Conclusion

The crude extract and its aqueous residue fraction showed a potent in vitro anticoagulant and membrane stabilizing activity, which shows the potential of the plant’s leaves as a new source of bioactive molecules for coagulation-related disorders.

Analysis of Chemical Composition and Assessment of Cytotoxic, Antimicrobial, and Antioxidant Activities of the Essential Oil of Meriandra dianthera Growing in Saudi Arabia

The essential oil of Meriandra dianthera (Konig ex Roxb.) Benth. (Synonym: Meriandra bengalensis, Lamiaceae) collected from Saudi Arabia was studied utilizing GC and GC/MS. Forty four constituents were identified, representing 96.8% of the total oil. The M. dianthera essential oil (MDEO) was characterized by a high content of oxygenated monoterpenes (76.2%). Camphor (54.3%) was the major compound in MDEO followed by 1,8-cineole (12.2%) and camphene (10.4%). Moreover, MDEO was assessed for its cytotoxic, antimicrobial, and antioxidant activities. MDEO demonstrated an interesting cytotoxic activity against all cancer cell lines with IC₅₀ values of 83.6 to 91.2 μg/mL, especially against MCF-7 cancer cells. Using labeling with annexin VFITC and/or propidium iodide (PI) dyes and flow cytometer analysis, the apoptosis induction was quantitatively confirmed for MCF-7 cells. The MDEO exhibited a considerable antimicrobial activity against all bacterial and fungal strains with minimum inhibitory concentration (MIC)-values of 0.07 to 1.25 mg/mL. The most sensitive microbial strain was Staphylococcus aureus (MIC: 0.07 mg/mL). Minimum bactericidal concentration (MBC) or minimum fungicidal concentration (MFC) values were determined one time higher than that of MIC’s. Additionally, the MDEO revealed a strong activity for reducing β-carotene bleaching with a total antioxidant value of 72.6% and significant DPPH free radical scavenging activity (78.4%) at the concentration 1000 μg/mL.