Nepeta humilis Bentham: First evaluation of phenolic profile and radical scavenging potential

Abstract

In traditional medicine, Lamiaceae plants are widely used as a cure for various health problems. Nepeta humilis is one of the Lamiaceae plants of Iranian-Turkish district growing naturally in the South East Anatolia. The present study was designed to investigate the radical scavenging activity and total phenolic content of Nepeta humilis as well as to determine the phenolic constituents of the extracts of flowers, leaves and roots using a previously validated RP-HPLC-DAD method for the first time. The total phenolic contents of flowers, leaves and roots were found as 123.18 ± 1.01, 66.20 ± 0.49 and 54.77 ± 1.23 mg GAE/g extract, respectively. In accordance with the higher total phenolic content, flower extract of the plant displayed more radical scavenging activity with both assays. HPLC results revealed that rosmarinic acid was detected as one of the main compounds in all the investigated parts of the plant, especially in the flowers (0.397 ± 0.01 g/100g dry weight). Also, chlorogenic acid, luteolin and apigenin were found in particular amount in the flower extract. Nepeta humilis is rich in phenolic compounds and can be evaluated as a promising antioxidant source.

Keywords

• Nepeta
• Lamiaceae
• radical scavenging
• HPLC
• phenolic compounds

References

1. [1] Formisano C, Rigano D, Senatore F. Chemical constituents and biological activities of Nepeta species. Chem Biodivers. 2011; 8: 1783-1817. [CrossRef]
2. [2] Aytac Z, Yıldız G. A new record for the Flora of Turkey. Turk J Bot. 1996; 20(4): 385–387.
3. [3] Köksal E, Tohma H, Kılıç Ö, Alan Y, Aras A, Gülçin İ, Bursal E. Assessment of antimicrobial and antioxidant activities of Nepeta trachonitica: Analysis of its phenolic compounds using HPLC-MS/MS. Sci Pharm. 2017; 85: 24. [CrossRef]
4. [4] Akdeniz M, Ertaş A, Yener I, Fırat M, Kolak U. Phytochemical and biological investigations on two Nepeta species: Nepeta heliotropifolia and N. congesta subsp. cryptantha. J Food Biochem. 2020; 44(2): e13124. [CrossRef]
5. [5] Kaska, A, Çiçek M, Mammadov R. Biological activities, phenolic constituents and mineral element analysis of two endemic medicinal plants from Turkey: Nepeta italica subsp. cadmea and Teucrium sandrasicum. S Afr J Bot. 2019; 124: 63-70. [CrossRef]
6. [6] Gökbulut, A. Validated RP-HPLC method for quantification of phenolic compounds in methanol extracts of aerial parts and roots of Thymus sipyleus and evaluation of antioxidant potential. Trop J Pharm Res. 2015; 14(10): 1871-1877. [CrossRef]
7. [7] Orhan Deliorman, D., Hartevioğlu, A., Orhan, N., Berkkan, A., Gökbulut, A., Günhan, Ö., Pekcan, M. Subacute effects of standardized Fumaria vaillantii Lois. ethanol extract on trace element levels, biochemical and histopathological parameters in experimental liver toxicity. J Food Biochem. 2016; 40: 180-189. [CrossRef]
8. [8] Nikam PH, Kareparamban J, Jadhav A, Kadam V. Future trends in standardization of herbal drugs. J App Pharm Sci. 2012; 2(6): 38-44. [CrossRef]

9. [9] Al-Dhabi NA, Arasu MV, Park CH, Park SU. Recent studies on rosmarinic acid and its biological and pharmacological activities. EXCLI Journal. 2014; 13: 1192–1195.
10. [10] Nasirkandi AM, Alirezalu A, Bahadori S. Phenolic compounds and antioxidant activity of Nepeta fissa - first report from Iran. Nat Prod Res. 2019, 10.1080/14786419.2019.1693566.[CrossRef]
11. [11] Sarıkürkçü C, Eskici M, Karanfil A, Tepe B. Phenolic profile, enzyme inhibitory and antioxidant activities of two endemic Nepeta species: Nepeta nuda subsp. glandulifera and N. cadmea. S Afr J Bot. 2019; 120: 298-301. [CrossRef]
12. [12] Kaska A, Deniz N, Çiçek M, Mammadov R. Evaluation of antioxidant properties, phenolic compounds, anthelmintic, and cytotoxic activities of various extracts isolated from Nepeta cadmea: An endemic plant for Turkey. J Food Sci. 2018; 83(6): 1552-1559. [CrossRef]
13. [13] Sharma A, Cannoo DS. Effect of extraction solvents/techniques on polyphenolic contents and antioxidant potential of the aerial parts of Nepeta leucophylla and the analysis of their phytoconstituents using RP-HPLC-DAD and GC-MS. RSC Advances. 2016; 6: 78151-78160. [CrossRef]
14. [14] Barros L, Baptista P, Ferreira ICFR. Effect of Lactarius piperatus fruiting body maturity stage on antioxidant activity measured by several biochemical assays. Food Chem Toxicol. 2007; 45: 1731-1737. [CrossRef]
15. [15] Re R, Pellegrini N, Proteggente A, Pannala A, Yang M, Rice-Evans C. Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radical Bio Med. 1999; 26: 1231-1237. [CrossRef]
16. [16] Singleton VL, Orthofer R, Lamuela-Raventos RM. Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin– Ciocalteu reagent. Method Enzymol. 1999; 299: 152–178. [CrossRef]