Valorization perspectives of agro-bio waste in pharmaceutics : examples of Moso bamboo leaves and rose oil distillation waste water

Liquid and solid agro-bio waste consists of complex molecules, and depicts the residue of which the nutritionally valuable portion has been removed. Depending on its origin and constitution, the waste fraction can be pernicious for the environment. In cases of further processing of these residues to value-added products, it is possible to reduce or even avoid waste fractions and thereby reach a sustainable way of production. This relatively modern approach is referred to as valorization and regarded an environmentally friendly practice since it expands the whole production process and thereby increases the degree of utilization. The raw material for valorization-accessible matter predominantly is generated as by-products in the agricultural cultivation and the food manufacturing industry, which depict the first two steps in the food supply chain. Realizing valorization procedures without affecting the quality of the original product requires detailed knowledge about the composition of the waste fraction and other characteristics to assess its fields of application. Therein, inadequate biological stability, potentially pathogenic nature, high water content, potential for rapid auto-oxidation or a high level of enzymatic activity among others are limitation factors. Based on this concept, we investigated in pharmaceutical purposes of waste fractions of two different species: Moso bamboo (Phyllostachys edulis) and the Damask rose (Rosa damascena). In this context, particularly anti-inflammatory parameters, as well as wound-closure characteristics were of interest.
The first part of this work is elucidating moso bamboo (Phyllostachys edulis)-derived compounds. Moso bamboo wood is utilized in many different sections of predominantly Chinese handicrafts. Furthermore, bamboo sprouts are edible and pose an important ingredient in far eastern cuisine. Due to the plant’s fast growth of up to one meter per day, it depicts a potentially convenient resource for sustainable use of the wood. However, also tons of polyphenol containing leaves accrue during the harvest with no further pharmaceutical profit up-to-date. Since polyphenols are known for their multifaceted biological activities, leaf extracts of Phyllostachys edulis were in the center of interest in terms of anti-inflammatory effects and wound closure activity on immortalized human keratinocytes and 3T3-swiss albino mouse fibroblasts. Therefore, levels of TNF-α-induced cytokines like IL-6, IL-8 and VEGF under influence of the extracts and its major single polyphenol isoorientin, respectively, were analyzed. Wound closure characteristics were evaluated employing a computerized modification of the classical scratch assay involving time lapse microscopy. It could be demonstrated an improvement of wound closure activity under influence of bamboo leaf extract (BLE) at moderate concentrations. At higher concentrations, BLE inhibited wound closure without impairing cell viability. The effect of isoorientin was comparable. Furthermore, BLE reduced TNF-α-induced VEGF and IL-8 levels in HaCaT keratinocytes, isoorientin caused significant reduction of the cytokines in a dose-dependent manner. Generally, anti-inflammatory effects were determined moderately, since cytokine-levels of untreated cells could not be reached.
The second and main part of the project analyzes biological activities of by-products of the Bulgarian rose oil production. Rose oil is basically used for both as a food ingredient and in cosmetic formulations. As the world’s main rose oil producer, Bulgaria cultivates the oil-bearing rose Rosa damascena in the Rose Valley producing more than 2000kg of the essential oil per year. Each kilogram of flowers requires the four-fold quantity of water for further processing. The multi-step water steam distillation is meticulous, however, about 30.000 tons of polyphenol containing, bio-polluting waste water accumulate annually. This figure provides a first insight to recognize rose oil distillation waste water (RODW) as a substantial toxic factor. There is no effective post-production residue management in Bulgaria up-to-date.
Purification of RODW resulted in a polyphenol depleted and a polyphenol enriched fraction [(RF20-(SP-207)], of which the latter one was split into four sub-fractions F(I)-F(IV) depending on the analytical spectrum of polyphenolic compounds. In a dose-dependent fashion, RF20-(SP-207) revealed anti-proliferative properties in human keratinocytes determined by ELISA-based bioassays. Time-lapse microscopy detected a significant impairment of cell migration under influence of RF20-(SP-207) and F(IV), respectively. TNF-α induced VEGF-secretion was significantly reduced by both substances likewise. Since there is a close interplay between cell locomotion and inflammatory processes, the anti-inflammatory properties of both RF20-(SP-207) and F(IV) were elucidated utilizing reverse transcriptase polymerase chain reaction (RT-PCR). RF20-(SP-207) and F(IV) significantly decreased the gene expression and cellular protein secretion of IL-1β, IL-6, IL-8, RANTES and MCP-1 and therefore, markedly modified inflammatory parameters in vitro.