A sedge plant as the source of Kangaroo Island propolis rich in prenylated p-coumarate ester and stilbenes

Abstract

Propolis samples from Kangaroo Island, South Australia, were investigated for chemical constituents using high-field nuclear magnetic resonance spectral profiling. A type of propolis was found containing a high proportion of prenylated hydroxystilbenes. Subsequently, the botanical origin of this type of propolis was identified using a beehive propolis depletion method and analysis of flora. Ligurian honey bees, Apis mellifera ligustica Spinola, were found to produce propolis from resin exuded by the Australian native sedge plant Lepidosperma sp. Montebello (Cyperaceae). The plants, commonly known as sword sedge, were found to have resin that matched with the propolis samples identified as the most abundant propolis type on the island containing C- and O-prenylated tetrahydroxystilbenes (pTHOS) in addition to a small amount of prenylated p-coumarate. The isolation of five pTHOS not previously characterized are reported: (E)-4-(3-methyl-2-buten-1-yl)-3,4',5-trihydroxy-3'-methoxystilbene, (E)-2,4-bis(3-methyl-2-buten-1-yl)-3,3',4',5-tetrahydroxystilbene, (E)-2-(3-methyl-2-buten-1-yl)-3-(3-methyl-2-butenyloxy)-3',4',5-trihydroxystilbene, (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,3',5,5'-tetrahydroxystilbene and (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,4',5-trihydroxy-3'-methoxystilbene. A National Cancer Institute 60 human cell line anticancer screen of three of these compounds showed growth inhibitory activity. The large Australasian genus Lepidosperma is identified as a valuable resource for the isolation of substances with medicinal potential.

Lessons from Exploring Chemical Space and Chemical Diversity of Propolis Components

“…In Australia, HBP collected in Kangaroo Island, South Australia, is unique with a large number of stilbenes accumulated from the exudates of the Australian native sedge plant Lepidosperma spp. [ 121 , 145 ]. The Kangaroo Island propolis displayed four times stronger antioxidant activity than the Brazilian green propolis [ 116 ].…”

“…The Kangaroo Island propolis displayed four times stronger antioxidant activity than the Brazilian green propolis [ 116 ]. The compound, 5,4′-dihydroxy-3,3′-dimethoxy-2-prenyl-( E )-stilbene, present in this propolis, inhibited the growth of cancer cell lines more potently than the anticancer agent tamoxifen ( Table 2 ) [ 145 ].…”

Antiplasmodial flavanones and a stilbene from Carpha glomerata

“…A unique doublet at δ H 6.70 (1H, d, J = 16.4 Hz, H-α) and δ H 7.06 (1H, d, J = 16.4 Hz, H-β) indicated an E -stilbene configuration. 13 The 1 H NMR spectrum showed signals at δ H 6.35 (2H, d, J = 2.2 Hz, H-2, H-6) and δ H 6.11 (1H, t, J = 2.1 Hz, H-4) indicating a 1, 3, 5-trisubstituted aromatic ring in A ring. The 1 H NMR spectrum combined with a 1 H- 1 H COSY spectrum displayed a pair of ortho aromatic protons at δ H 7.24 (1H, d, J = 8.6 Hz, H-6′) and δ H 6.72 (1H, d, J = 8.6 Hz, H-5′) of the ring.…”

Structure Elucidation and Botanical Characterization of Diterpenes from a Specific Type of Bee Glue

“…To further minimize mixing from different plant sources, propolis collections were restricted to a maximum of 1 kg per sample bag and every bag was analyzed. More than 1000 samples were analyzed by thin-layer chromatography (TLC) and 1 H-NMR studies and classified into six main propolis types; three types have been published [ 16 , 17 ] and the others are yet to be published [ 18 ]. Multiple propolis samples based on their relatively simple TLC and NMR pattern were identified as a likely single-source propolis of a type and initially named “purple spot” propolis (myoporum propolis) based on a characteristic purple spot observed by TLC and also purple coloration of the propolis and its ethanol solutions.…”