CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF KENAF LEAVES

Transcription

1 CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF KENAF LEAVES Andreia Pascoal 1,2 Ana Luísa Fernando 1, * Rosa Quirantes-Piné 2,3 Antonio Segura-Carretero 2,3 1 UBiA, DCTB, FCT-Universsidade Nova de Lisboa, Portugal 2 University of Granada, Spain 3 CIDAF, Granada, Spain 1

2 Kenaf (Hibiscus cannabinus L) Non-food crop High yields 9-22 ton/ha dm South mediterranean Root System Deep and long Drought tolerant High nutrient use efficiency 2 2

3 Kenaf (Hibiscus cannabinus L) Yielding high quality lignocellulosic material Both for energy and fibre production Cordage crop Paper products Building material Absorbents 3 3

4 Kenaf (Hibiscus cannabinus L) Seeds, flowers, leaves source of biopharmaceuticals pharmacological effects chemical composition poorly studied 4 4

5 Aim of the Study To identify the phenolic compounds To evaluate the antioxidant activity kenaf s leaves Everglades 41 and Tainung 2 produced in Portugal 5 5

6 Context 6 6

7 Bioactivity Context Plants: Sun exposure Oxidative damage Essences, Pigments, Taste Human organism: Anti-carcinogenic Anti-inflammatory Cardioprotective Food Bitterness Astringency Colour Flavour Odor Oxidative Stability 7 7

8 Phenolic Compounds Quantified in Samples: Antioxidant capacity DPPH, ORAC Total phenolic content Folin-Ciocalteu 8 8

9 Methodology Leaves harvested in September Before flowering Dried, stored in dark, room temperature Everglades 41 Tainung 2 9 9

10 Extraction methods - quantification Leaves 500 mg 15 ml MeOH 100% 15 ml MeOH 80% Overnight maceration 12h dark, room T, stir plate Ultrasound-assisted Extraction 2h untrasound, room T pellet Folin-Ciocalteu Centrifuged 15min, 4000 rpm 3x 10 DPPH ORAC Rotary evaporator 40ºC, dissolved in MeOH (1-2mL), filtered 0,45µm, -20ºC 10

11 Identification of phenolics - analytics HPLC-ESI-MS (Q-TOF)) Liquid chromatography coupled to electrospray ionization mass spectrometry using quadrupole time-of-flight analyzer 11 11

12 Results Consistent results 100% MeOH Ultrasound extraction Everglades

13 Results Consistent results 100% MeOH Ultrasound extraction Everglades

14 Results Everglades 41 Richer in polyphenols anti-oxidant activity 14 14

15 Results Everglades 41 Richer in polyphenols anti-oxidant activity μmol Trolox/mg sample 15 15

16 Results Everglades 41 Base peak chromatogram 47 compounds 16 16

17 Results 17 17

18 Results 18 18

19 Results. Tainung 2, only 37 compounds 19 19

20 Conclusions This study was a step forward for the comprehension of the phenolic compounds of Kenaf leaves The extraction system evaluated to be the best was the ultrasound-assisted extraction with 100% MeOH Results of Folin Ciocalteau, DPPH and ORAC pointed to Everglades 41 type to have more antioxidant potential and more phenolic contents 20 20

21 Future activities To study differences along growing cycle To study anti-mutagenic activities Evaluation on the activity of the leaves or extracts on polymeric materials (food packaging) 21 21

22 Conclusions Everglades 41 appeared to be richer in phenolic compounds, presenting 47 compounds against 37 from Tainung 2 Was possible to propose 28 compounds for the Everglades 41 type and 26 of those compounds were also proposed to be in the Tainung 2 type Some of the compounds found in the Kenaf leaf were related before with the Hibiscus genus 22 22

23 Acknowledgements This work was supported by the European Union project Fiber Crops as a Sustainable Source of Biobased Materials for Industrial Products in Europe and China, FIBRA) Erasmus program: grant attributed to Andreia Pascoal for her mission in Granada 23 23

24 Thank you for your attention 24 24