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Family Anacardiaceae
Rhus taitensis Guill.

Scientific names Common names
Duckera taitensis (Guill.) F.A.Barkley Malaiba (Tag.)
Melanochyla tomentosa Engl. Sumac (Engl.)
Melanococca tomentosa Blume Tahitian rhus (Engl.)
Rhus engleriana Warb.  
Rhus ferruginea Teijsm. & Binn. ex Engl.  
Rhus panaciformis F.Muell.  
Rhus retusa Zoll. ex Teijsm. & Binn.  
Rhus retusa var. blumei Engl.  
Rhus rufa Teijsm. & Binn.  
Rhus simarubifolia A.Gray  
Rhus simarubifolia var. taitensis (Guill.) Engl.  
Rhus taitensis Guill.  
Toxicodendron retusum (Zoll. ex Teijsm. & Binn.)  
Toxicodendron simarubifolia (A.Gray) Kuntze  
Otonychium retusum Miq.  
Rhus taitensis Guill. is an accepted name. KEW: Plants of the World Online

Other vernacular names
NIUEAN: Tavahi.
SAMOAN: Tavai.
TONGAN: Tavahi.

Gen info
- Rhus taitensis is a small tree of shrub in the sumac family of plants.
- There has been conflict on the treatment of the genus Rhus, some as a genus comprising of just 35 species, while others view it as a looser genus comprising about 250 species with several subgenera.     (3)
- The genus Rhus contains species with highly toxic or irritant sap, which as included in Toxicodendron. The poisonous species (Toxicodendron) have axillary panicles and smooth fruits, while the non-poisonous species (Rhus) have compound terminal panicles and fruits covered with acid crimson hairs. However, in susceptible people, there ie concern the sap of some species can cause a skin rash. (3)
- Rhus spp. are commonly referred to as 'sumac.' Rhus taitensis' has taken 'sumac' as a common name.

Rhus taitensis is a tree growing up to 30 m. Bole is cylindrical, sometimes with buttresses, up to 70 cm diameter. Exudate emerging from layers in the blaze. Lenticels often large and conspicuous, more than 1 cm diameter. Leaflet blades about 4-15 x 1.5-5 cm. Leaflets and twigs produce a milky exudate. Pulvinus usually apparent on the terminal leaflet. Inflorescence quite large and complex. Calyx lobes broadly ovate, about 0.8-1 mm long. Petals narrowly ovate, elliptic or obovate, glabrous outside, pilose inside for the lower half, about 2-2.5 mm long. Disk 10-lobed. Stamens inserted outside the disk, filaments about 1-1.2 mm long , anthers about 0.8-1 mm long. Fruits produced in great abundance. Fruits ovoid, but laterally compressed, about 6-8 x 4-8 mm. Seeds enclosed in a hard endocarp. Seeds flattened, about 2-3 mm diam. Cotyledones 3-veined. (2)

Rhus taiteneis is a large tree up to 30 m or more in height, with puberulent young stems and with the trunk base typically extending into low buttresses; bark mottled brown, rough, inner bark red-brown to pink oozing white sap, wood cream-colored. Leaves odd- (sometimes even-) pinnately compound, alternate, rachis mostly 15-50 cm long, pubescent, leaflets 7-19, opposite or sometimes alternate, blades mostly elliptic, 4-20 cm long, reddish when young, oblique at the base, rounded or broadly acute to acuminate at the tip; surfaces pubescent to subglabrous,l upper side darker with red to yellow veins, veins of lower side often pubescent; margins entire; petiolule 1-5 mm long. Inflorescence a terminal or upper-axillary, widely branching, many-flowered panicle 8-30 cm long, with a densely pubescent axis; flowers unisexual, trees dioecious. Calyx deeply divided into 5 subround lobes 0.5-1 mm long, subsessile. Corolla rotate, with 5 white to pink, orbicular petals 1.5-2 mm long. Ovary of female flower superior; styles 3, each with a short terminal stigma; ovary vestigial in the male flower. Stamens  of male flowers 5, free, absent in the female flowers. Fruit a shiny black, compressed-ellipsoid drupe 3-5 mm in diameter. Flowering typically from March to September (but sometimes beyond this, e.g., December), fruiting during most months (and perhaps persisting on the inflorescence), but not at the same time as flowering, with a peak from April to October (Trail n.d.). Distinguished by its large tree habit; milky sap; alternate, odd-pinnately compound leaves that are reddish when young; large dense panicles of tiny white to pink, 5-parted flowers; and small, shiny black drupes. (Rainforest Trees of Samoa) (8)

- Native to the Philippines.
- Grows primarily in the wet tropical biome.
- Also native to Bismark Archipelago, Caroline Is., Cook Is., Fiji, Jawa, Lesser Sunda Is., Maluku, Marianas, New Guinea, Niue, Queensland, Samoa, Society Is., Solomon Is., Sulawesi, Tonga, Vanuatu, Wallis-Futuna Is.
- In primary dryland rain-forest, in inundated forest along rivers, in clearings, secondary forests or savannahs, at sea level up to 1,950 meters.

- Study of petrol extract of leaves isolated a new lupane type triterpene, 3ß,20,25-trihydroxy lupane, together with known compounds, 3,20-dihydroxylupane (1), 20-hydroxylupane-3-one (2), 20,28-dihydroxylumpane-3-one (3), 3,16-dihydroxy lupa-20(29)-ene (4) and 28-hydroxy-ß-amyrone. (5)
- Bioassay-guided fractionation of methanolic extract of Rhus taitensis leaves and twigs isolated a new triterpene, tetrahydroxysqualene (1).(see study below) (5)
Study of leaves and twigs isolated two new triterpenoids, namely: 1,10,24,25,30-pentahydroxysqualene (1), and dammar-2-(22),24-diene-3ß,26,27-triol (2). (see study below) (6)

- Studies have suggest antimycobacterial tuberculosis properties.

Parts used
Leaves, twigs.



- No reported folkloric medicinal use in the Philippines.
- In Tahiti, used for treatment of diarrhea; in the Solomon Is., used for deafness. (75)

Tetrahydroxysqualene / Antimycobacterial / Leaves and Twigs:
Bioassay-guided fractionation of methanolic extract of Rhus taitensis leaves and twigs isolated a new triterpene, tetrahydroxysqualene (1). The compound exhibited antituberculosis activity with MIC of 10.0 µg/mL, while showing only modest cytotoxicity. (5)
New Antimycobacterial Triterpenoid / Leaves and Twigs: Study of leaves and twigs isolated two new triterpenoids, namely: 1,10,24,25,30-pentahydroxysqualene (1), and dammar-2-(22),24-diene-3ß,26,27-triol (2). Both compounds exhibited moderate antimycobacterial activities with MIC of 45 µg/mL. (6)


January 2023

                                                 PHOTOS / ILLUSTRATIONS
IMAGE SOURCE: Photograph: Rhus taitensis - flowering / Tau'olunga / CC by SA 3.0 / click on image to go to source page / Wikipedia
OTHER IMAGE SOURCE: Photo / Anacardiaceae: Rhus taitensis -- Abaxial view of leaf / Copyright © 2017 by P B Pelser & J F Barcelona (contact: pieter.pelser@canterbury.ac.nz) [ref. DOL119670] / Non-Commercial Use / click on image to go to source page / Phytoimages.siu.edu
OTHER IMAGE SOURCE: Photo / Anacardiaceae Rhus taitensis -- fruits and leaves / Copyright © Guide to Trees of Papua New Guinea / Barry Conn and Kipiro Damas  / Non-Commercial Use / click on image to go to source page /  PNGTreesKey

Additional Sources and Suggested Readings
Rhus taitensis Guill. / KEW: Plants of the World Online

Rhus taitensis Guill. / Australian Tropical Rainforest Plants
Rhus taitensis / Ken Fern - Tropical Plants  Database / Useful Tropical Plants
Triterpenes from Rhus taitensis / Aysen Yürüker, Jimmy Orjala, Otto Sticher, Topul Rali / Phytochemistry, 1998; 48(5): pp 863-866
Tetrahydroxysqualene from Rhus taitensis Shows Antimycobacterial Activity against Mycobacterium tuberculosis / Jeffrey C Noro, Louis R Barrows, Osia G Gideon, Tim S Bugni et al / J Nat Prod., 2008; 71(9): pp 1623-1624 / DOI: 10.1021/np800082e
New Antimycobacterial Triterpenoids from Rhus taitensis / Raquel C Jadulco, Michael Koch, Ryan M Van Wagoner, Louis R Barrows et al / Natural Product Chemistry, 2011; 77(14): pp 1651-1654 /
DOI: 10.1055/s-0030-1271027
Rhus taitensis / USDA: Dr duke's Phytochemical and Ethnobotanical Databases
Rhus taitensis / PIER: Pacific Island Ecosystems at Risk

DOI: It is not uncommon for links on studies/sources to change. Copying and pasting the information on the search window or using the DOI (if available) will often redirect to the new link page. (Citing and Using a (DOI) Digital Object Identifier)

                                                            List of Understudied Philippine Medicinal Plants

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