Formulation Process Analysis of a Virus-based Biopesticide to Control the Tomato leafminer Tuta absoluta

Abstract: Virus-based biopesticides are effective biocontrol agents of crop insect pests. Development of suitable formulations and production processes are necessary to obtain high-quality products easily adopted by farmers. A detailed unit operation study was carried out for the production process of a Phthorimaea operculella granulovirus-based biopesticide to control the tomato leafminer, Tuta absoluta, one of the most important pests affecting this crop. Physicochemical, microbiological, and insecticidal parameters were implemented in the process and applied to the finished product, and a scaling strategy was developed. A Quantitative Polymerase Chain Reaction (Q-PCR) technique was implemented to quantify viral concentrations in the active ingredient (5.34 ± 1.44 x109 Occlusion Bodies mL-1) and in the finished product (>1.6x109 OB mL-1), without contaminant interferences. The Q-PCR methodology was also useful to select the appropriate solid mixing time following Lacey´s mixing index (8 min). Factors and similarity principles influencing the liquid mixing process were identified in the scaling evaluation. Furthermore, the drying kinetics analysis enabled identifying a drying temperature of 35 °C, with an efficacy under controlled conditions higher than 97%. Contaminant concentration was lower than 1%, indicating controlled and aseptic formulation process conditions. A simple statistical method was used to estimate the reproducibility and repeatability of the parameters assessed in the finished product. These results enable to establish and extrapolate important parameters in the standardization, scale-up, and quality control for the granulovirus-based biopesticide.

Bioactive compounds in Bidens pilosa L. populations: a key step in the standardization of phytopharmaceutical preparations

The total flavonoid content (TFC), total polyphenols content (TPC), and in vitro antioxidant activity (AA) of six Bidens pilosa L., Asteraceae, populations harvested from different localities were evaluated in this work. The plants were separated in roots, stems, and leaves/flowers, and the influence of extraction methods was investigated.Areversed-phase high-performance liquid chromatography method (HPLC) was developed and employed to obtain characteristic HPLC fingerprints of the bioactive compounds present in the extractive solutions, which were correlated with the TFC, TPC, and AA. Extractive solutions of leaves/flowers presented a higher AA when compared with those obtained from other parts of the plant (IC50 of 35.35±0.10 µg/mL). The stem extracts presented the lowest AA (IC50 117.2±1.96 µg/mL). A direct correlation of AA with TFC and TPC was evidenced. The highest AA was obtained by dynamic maceration and was statistically different from the AA presented by the extractive solutions obtained by other extraction methods. The results of this work evidenced differences that can be found at different stages of development of phytopharmaceutical preparations from B. pilosa and highlighted the importance of using the concentration of marker compounds as well as HPLC fingerprints as quality control parameters.