Microwave-assisted extraction of the gallic acid biomarker from Acacia arabica bark followed by HPLC analysis

Document Type : Original Article


Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Ain Shams University, Abbassia, Cairo 11566, Egypt


An efficient and fast microwave-assisted extraction (MAE) technique was developed for extracting gallic acid as an indicative biomarker for the quality control of Acacia arabica bark. The MAE technique was optimized and compared with other conventional extraction techniques. The optimal conditions of MAE were 20% methanol as solvent, solid/liquid ratio 1:40 (g/mL), irradiation power 20% and two extraction cycles, 5 min each. The proposed extraction technique produced a maximum yield of 10.59 (mg/g) gallic acid in 10 min, which was 1.03 and 1.15 times more efficient than 6 h of heat reflux and 24 h of maceration extraction, respectively. This high yield, along with saving of time, energy, and solvent would position MAE as a valuable and cost-effective technology suitable for today's highly competitive industries, with growing demand for increased productivity, improved efficiency, and reduced cycle time. Moreover, a new high-performance liquid chromatography method was developed and validated for the determination of gallic acid in Acacia arabica bark extract. The method was found to be rapid, sensitive, accurate, precise, and robust. The method showed good linearity over concentration range 1-100 (µg/mL) with LOD 16.08 (ng/mL) and LOQ 48.73 (ng/mL). The average recovery obtained using standard addition technique was 100.36% with a low value of RSD% (1.19%) indicating the accuracy of the proposed method for determination of gallic acid in Acacia arabica bark extract. 


1. Ali A, Akhtar N, Khan BA, Khan M S, Rasul A, Shahiq-UZ-Zaman, Khalid N, Waseem K, Mahmood T, Ali L. Acacia nilotica: A plant of multipurpose medicinal uses. J Med Plant Res 2012; 6:1492-6.
‏‏2. Punithavathi VR, Prince PS M, Kumar R, Selvakumari J. Antihyperglycaemic, anti-lipid peroxidative and antioxidant effects of gallic acid on streptozotocin-induced diabetic Wistar rats. Eur. J. Pharmacol 2011; 650:465-471.
3. Yen GC, Duh PD, Tsai H L. Antioxidant and pro-oxidant properties of ascorbic acid and gallic acid. Food Chem. 2002; 79: 307-313.
4. You BR, Moon, HJ, Han, YH, Park, WH. Gallic acid inhibits the growth of HeLa cervical cancer cells via apoptosis and/or necrosis. Food Chem. Toxicol. 2010; 48:1334-1340.
5. Yoon CH, Chung SJ, Lee SW, Park YB, Lee SK, Park, MC.  Gallic acid, a natural polyphenolic acid, induces apoptosis and inhibits proinflammatory gene expressions in rheumatoid arthritis fibroblast-like synoviocytes. Joint Bone Spine 2012; 80:274–279.
6. Kim YJ. Antimelanogenic and antioxidant properties of gallic acid. Biol. Pharm. Bull. 2007; 30:1052-1055.
7. Kang MS, Oh JS, Kang IC, Hong SJ, Choi CH. Inhibitory effect of methyl gallate and gallic acid on oral bacteria. J Microbiology. 2008; 46:744-750.
8. Kratz JM, Andrighetti-Fröhner C R, Leal P C, Nunes R J, Yunes R A, Trybala E, Bergström TBarardi C R, Simões CM O. Evaluation of anti-HSV-2 activity of gallic acid and pentyl gallate. Biol. Pharm. Bull. 2008; 31: 903-907.
9. Mansouri MT, Farbood Y, Sameri MJ, Sarkaki A, Naghizadeh B, Rafeirad M. Neuroprotective effects of oral gallic acid against oxidative stress induced by 6-hydroxydopamine in rats.  Food Chem. 2012; 138:1028-1033
10. Priscilla DH, Prince P. Cardioprotective effect of gallic acid on cardiac troponin-T, cardiac marker enzymes, lipid peroxidation products, and antioxidants in experimentally induced myocardial infarction in Wistar rats. Chem. Biol. Interact.2009; 179:118-124.
11. Sasidharan S, Chen Y, Saravanan D, Sundaram KM, Latha LY. Extraction, isolation, and characterization of bioactive compounds from plant's extracts. Afr J Tradit Complement Altern Med. 2011; 8:1-10.
12. Nyiredy S. Separation strategies of plant constituents–current status. J. Chromatogr. B Biomed. Sci. Appl. 2004; 812:35-51.
13. Luque de Castro MD, Garcı́a-Ayuso LE, Soxhlet extraction of solid materials: an outdated technique with a promising innovative future, Anal. Chim. Acta. 1998; 369:1-10.
14. Mandal V, Dewanjee S, Mandal SC. Microwave-assisted extraction of total bioactive saponin fraction from Gymnema sylvestre with reference to gymnemagenin: a potential biomarker. Phytochem Anal. 2009; 20:491-497.
15. Mandal V, Mohan Y, Hemalatha S. Microwave-assisted extraction – an innovative and promising extraction tool for medicinal plant research. Pharmacogn Rev. 2007; 1:7-18.
16. Yan M M, Liu W, Fu YJ, Zu YG, Chen CY, Luo M. Optimisation of the microwave-assisted extraction process for four main astragalosides in Radix Astragali. Food Chem. 2010; 119:1663-1670.
17. Fang X, Wang J, Zhang S, Zhao Q, Zheng Z, Song Z. Simultaneous extraction of hydrosoluble phenolic acids and liposoluble tanshinones from Salviae miltiorrhizae radix by an optimized microwave-assisted extraction method. Sep Purif Technol. 2012; 86:149-156.
18. Wakte PS, Sachin BS, Patil AA, Mohato DM, Band TH, Shinde DB. Optimization of microwave, ultra-sonic and supercritical carbon dioxide assisted extraction techniques for curcumin from Curcuma longa. Sep Purif Technol. 2011; 79: 50-55.
19. Hayat K, Hussain S, Abbas S, Farooq U, Ding B, Xia S, Jia C, Zhang X, Xia W. Optimized microwave-assisted extraction of phenolic acids from citrus mandarin peels and evaluation of antioxidant activity in vitro. Sep Purif Technol. 2009; 70: 63-70.
20. Madej K. Microwave-assisted and cloud-point extraction in the determination of drugs and other bioactive compounds, Trends Analyt Chem. 2009; 28:436-446.
24. Stationery Office. British Pharmacopoeia 2010. London: UK.
25. Letellier M, Budzinski H, Charrier L, Capes S, Dorthe AM. Optimization by factorial design of focused microwave-assisted extraction of polycyclic aromatic hydrocarbons from marine sediment. Fresenius J Anal Chem 1999; 364: 228-237.
26. Fulzele DP, Satdive RK. Comparison of techniques for the extraction of the anti-cancer drug camptothecin from Nothapodytes foetida. J Chromatogr 2005; 1063:9-13.
27. Waksmundzka-Hajnos M, Petruczynik A, Dragan A, Wianowska D, Dawidowicz AL, Sowa I. Influence of the extraction mode on the yield of some furanocoumarins from Pastinaca sativa fruits. J Chromatogr B Biomed Sci Appl 2004; 800: 181-187.
28. Zhang B, Yang R, Liu C Z. Microwave-assisted extraction of chlorogenic acid from flower buds of Lonicera japonica Thunb. Sep Purif Technol 2008; 62:480-483.
29. Wang Y L, Xi G, Zheng Y, Miao F. Microwave-assisted extraction of flavonoids from Chinese herb Radix puerariae (Ge Gen). J Med Plant Res 2010; 4:304-308.
30. Chen L, Jin H, Ding L, Zhang H, Li J, Qu C, Zhang H. Dynamic microwave-assisted extraction of flavonoids from Herba Epimedii. Sep Purif Technol 2008; 59:50-57.
31. Sparr Eskilsson C, Björklund E. Analytical-scale microwave-assisted extraction, J Chromatogr 2000; 902:227-250.
32. Dhobi M, Mandal V, Hemalatha S, Optimization of microwave-assisted