Ellagitannins from Raspberry (Rubus idaeus L.) Fruit as Natural Inhibitors of Geotrichum candidum

Abstract

Abstract:The paper presents the chemical characteristics of ellagitannins isolated from raspberry (Rubus idaeus L.) fruit and their in vitro and in situ antifungal activity against Geotrichum candidum ŁOCK 0511. The study investigated a complex preparation containing various raspberry ellagitannins at a concentration of 86% w/w, as well as pure lambertianin C and sanguiin H-6. The ellagitannin preparation was obtained by extracting raspberry press cake and purifying the extract using Amberlite XAD resin, while individual compounds were isolated by means of preparative HPLC. The complex preparation was analyzed for the content of ellagitannins, anthocyanins, and flavan-3-ols using HPLC and LC-MS. The antifungal activity of the complex ellagitannin preparation and the isolated ellagitannins was determined for the strain Geotrichum candidum. The MIC and MFC values (10.0 mg/mL and 30.0 mg/mL, respectively) were found to be the same for lambertianin C, sanguiin H-6, and the complex ellagitannin preparation. The fungistatic activity of the studied ellagitannin preparation at a concentration of 10 mg/mL, as determined by the poisoned medium method, was 65.2% following 6 day incubation of Geotrichum candidum, with the linear growth rate of only 16.2 mm/day. The corresponding parameters for the control sample were 0% and 56 mm/day, respectively. The study demonstrated both in vitro and in situ antifungal activity of raspberry ellagitannins against Geotrichum candidum.

Stability and transformations of raspberry (Rubus idaeus L.) ellagitannins in aqueous solutions

“…The study material was raspberry ellagitannin preparation (REP), which contained 44% lambertianin C and 35% sanguiin H-6. The full method of REP production was detailed in our previous publication [15]. Briefly, raspberry pomace from juice manufacture was extracted with 60% acetone.…”

The antimycotic effect of ellagitannins from raspberry (Rubus idaeus L.) on Alternaria alternata ŁOCK 0409

“…The formula containing 765 mg/g of ellagitannins produced from raspberry fruit (Rubus idaeus L.) according to the procedure described previously [15] was used as the experiment material. The formula was made of fruit pomace after production of juice, in laboratory conditions, from the 'Polka' variety raspberries purchased from the Cajdex company (Łódź, Poland).…”

“…Content of individual ellagitannins, total flavanol and total anthocyanin content were determined in the formula. The qualitative and quantitative analysis of ellagitannins and other polyphenols was completed according to the previously described procedure, using the same research equipment [15]. Briefly, the UHPLC Dionex Ultimate 3000 chromatograph (Germering, Germany) with the mass detector Q Exactive Orbitrap (Thermo Fisher Scientific, Bremen, Germany) was used for the qualitative analysis of ellagitannins.…”

“…To generate MS 2 data the normalized collision energy (NCE) was set to 20 eV in HDC collision cell. The identification of researched ellagitannins was the same as described in our previous publication [15].…”

“…Ellagitannins were separated on Gemini C18 110A column 250 × 4.6 mm i.d., 5 μm (Phenomenex) by gradient elution with 0.05% (v/v) phosphoric acid in water (solvent A), and 83:17 (v/v) acetonitrile:water with 0.05% phosphoric acid (solvent B). The column temperature was set to 35 °C, the flow rate was 1.25 ml/min, and the gradient program the same as described in our previous work [15]. Ellagitannins were detected at 250 nm, and standard curves for lambertianin C and sanguiin H-6 were used for quantification.…”