Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 1st International Congress on Bioactive Compounds and 2nd International Workshop on Bioactive Compounds - Vol. 1 - 2018

IIntroduction
Food production, as food and pharmaceutical industry will be affected by climate change in the next years. Therefore, it is an essential trait to find new food matrices for those sectors in the world, focusing on native plants that could tolerate the changing environment. Curcuma zedoaria (Christm.) Roscoe is a native plant from Bangladesh, Sri Lanka and India, which presents medicinal, food and health proprieties. C. zedoaria rhizomes produce essential oils that must be able to tolerate water deficiency, which could be an alternative resource for the food industry. In this way, is crucial to observe the essential oil production in plants that experienced water deficiency, looking for evidences of similar metabolic patterns.

• Objectives
Observe the interference of water deficiency on the chemical volatile profile of C. zedoaria essential oils.

• Methods
The experiment was conducted in a greenhouse under experimental conditions (TºC±25 °C; RH±70%). Plants were divided into control treatment (CT, n = 6), with maximum water capacity, and water deficit treatment (WDT, n = 6) without irrigation. We measured the water potential from leaves, water potential substrate, and relative water content on leaves until leaf fall. After leaf fall, rhizomes were collected to characterize the essential oil content of CT and WDT treatments (n=3, each). Essential oil was extracted by hydrodistillation with Clevenger apparatus, and quantitative analysis was made by gas-chromatograph GC (Shimadzu GC-2010) equipped with flame ionization (GC–FID) and using a DB-5 (J and W Scientific; 30 m × 0.25 mm × 0.25 mm × 0.25 μm) capillary column, with detector at 230 ̊C, drag gas: Helium, flow rate: 1.0 mL / min; split: 1/20. Program temperature: 60 °C - 240 °C, 3 °C.min-1. Qualitative analysis was made by gas chromatography with mass spectrometer (GC-MS, Shimadzu, QP-5000), operating by impact of electrons (70 eV), with silica capillary column OV-5 Ohio Valley Specialty Chemical, Inc. (30.0m x 0.25mm x 0.25μm), following the same configuration of GC/FID. Substances were identified by mass spectra (NIST 62.lib) and Retention Index.

• Results and discussion
Water stressed plants presented more essential oil content than control plants (WDT=0.58±0.17; CT=0.43±0.13). Chemical volatile profiles indicated that hydrocarbon monoterpenes declined during water deficiency (CT=9.1%; WDT=7.5%), and the same behavior was noted by oxygenated monoterpenes (CT=60.0%; WDT=48.5%). On the other hand, oxygenated sesquiterpenes rose up during water stress (CT=18.6%; WDT=29.4%). Furthermore, the major compounds of C. zedoaria also varied between treatments, such as 1,8-cineole (CT=39.7%; WDT= 29.2%, p=0.05143), and camphor (CT=14.8%; WDT=13.1%, p=0.1108), but only curzerenone presented significant difference about production (CT=16.1; WDT=24.3, p=0.04268). Instead of variations of class of essential oil substances, and major compounds content indicate that this plant changes the production of mono sesquiterpenes during water stress events, substances with industrial interests, such as 1,8-cineole and camphor does not alter their relative amounts. Moreover, drought stimulates curzerenone production in rhizomes, which could be an alternative in producing new essential oils with stronger food proprieties.

• Conclusions
The chemical profile of essential oils from C. zedoaria rhizomes presents several oscillations of mono and sesquiterpene content, but several major compounds are still the same even during water deficiency. These results could bring different alternatives to manipulate essential oils production in a potential plant used for the food industry.