Cucurbitacins B, E and I Concentrations and Relationship with Drought Tolerance in Bottle Gourd [Lagenaria siceraria (Molina) Standl.]

Abstract

Bottle gourd [Lagenaria siceraria (Molina) Standl.]) is a relatively drought-tolerant cucurbit due to the high composition of unique biochemical compositions, including cucurbitacin. The objective of this study was to determine the concentrations of cucurbitacins in bottle gourd and their relationship to drought tolerance. The study assessed 12 bottle gourd accessions grown under two moisture levels (i.e., non-stressed (NS) and drought-stressed (DS)) and three drought stress intensities (i.e., mild, moderate, and severe) using a 12 × 2 × 3 factorial experiment designed in a randomized complete block design with three replications. Control studies were undertaken under glasshouse conditions. The content of cucurbitacins B, E, and I were quantified in leaves and roots using high-performance liquid Cchromatography–mass spectrometry (HPLC-MS). The free radical scavenging activities of pure cucurbitacins B, E, and I were quantified using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and a ferrulic acid power assay (FRAP). Results revealed that cucurbitacins B and I were present in accessions BG-48, BG-58, BG-70, BG-78, BG-79, BG-81, BG-52, and GC in leaves and roots under DS condition. The contents of cucurbitacins B and I were enhanced under increased drought intensity for accessions BG-48, BG-81, and GC. In all the leaf and root samples, cucurbitacin E was not detectable. Based on the DPPH test, pure cucurbitacins I, B, and E reduced free radicals at maximum values of 78, 60, and 66%, respectively. Based on the FRAP assay, pure cucurbitacins I, B, and E had maximum ferric-reducing powers of 67, 62, and 48%. Additionally, cucurbitacin I recorded the highest antioxidant activity compared to cucurbitacins B and E. Increased cucurbitacin accumulation and antioxidant properties indicate their role in minimising cell damage caused by oxidative stress under drought-stressed environments. The present study revealed that cucurbitacins B and I serve as novel biochemical markers for screening drought tolerance in bottle gourd or related cucurbits.

Total cucurbitacins from Herpetospermum pedunculosum pericarp do better than Hu-lu-su-pian (HLSP) in its safety and hepatoprotective efficacy

“…It demonstrated that TCs can decrease oxidative stress and protect cell membranes from oxidative damage. This result is consistent with a previous study that CuB and CuE minimised cell damage caused by oxidative stress under drought-stressed environments ( Mkhize et al, 2023 ). Since the liver is the primary site of amino acid metabolism ( Ammar et al, 2022 ), CCl 4 injury leads to the disruption of amino acid metabolism.…”

“…The cold and drought environment upregulates genes related to cucurbitacin synthesis in H. pedunculosum , resulting in higher levels of CuB and its isomer compared to C. melo . This finding is consistent with literature showing cucurbitacin accumulation increases under drought stress ( Mkhize et al, 2023 ). Ultimately, growing in different climates impacts the plant biochemistry and results in divergence of therapeutic efficacy and safety between taxa ( Panossian, 2023 ), warranting further evaluation of understudied species like H. pedunculosum that may have unexplored benefits.…”