Lambda 5 spectrophotometer

Optical rotations were measured at 20 °C in methanol using an Anton Paar MCP 300 polarimeter (Anton Paar, Graz, Austria) in a 100 mm long 350 μL cell. UV spectra for pure molecules were recorded at 20 °C in methanol using a PerkinElmer Lambda 5 spectrophotometer. NMR spectra were recorded on Bruker 500 MHz and 700 MHz spectrometers (Bruker, Rheinstetten, Germany). The chemical shifts (δ) are reported as ppm based on the solvent signal, and coupling constants (J) are in hertz. All solvents were HPLC grade, purchased from Sigma-Aldrich (Saint-Quentin-Fallavier, France).

Dried crude extracts were resuspended at 1 mg.mL⁻¹ in analytical grade methanol. UV spectra for crude extract were recorded at 20 °C in analytical grade methanol using a PerkinElmer Lambda 5 spectrophotometer. Acquisition was made from 800 nm to 200 nm with scan interval of 1 nm and scan rate of 600 nm.min⁻¹. Light source changeover from visible to UV was made at 350 nm. The OD yield at 400, 460 and 500 nm was obtained using the following formula:
OD_nm = (Absorbance_nm) × (Dilution factor) × (Dried Crude extract mass)/(Petri dish mass), and is given in arbitrary unit_nm per gram of solid medium (AU_nm.g⁻¹ of solid medium).