Lamiaceae: key achievements 2006 - 2011

The multidisciplinary work of the Lamiaceae Team includes displays of horticulturally important genera, writing accounts for much-needed tropical floras and producing conservation assessments, conducting molecular phylogenetic studies of poorly understood groups within the family and analysing members of the family for biologically active compounds.

Over the five-year reporting period, we have completed the account of Lamiaceae for Flora of Tropical East Africa with 327 species in 30 genera, including a preliminary conservation assessment for each species (Paton et al. 2009). The account for Flora Zambesiaca is in press and includes 266 species in 28 genera. There has been progress in our understanding of the phylogenetic relationships in tribe Ocimeae with a particular focus on the large genera Plectranthus and Hyptis. A molecular phylogenetic study of Hyptidinae has been accepted for publication. The large paraphyletic Hyptis has been divided into monophyletic genera and resultant name changes have also been submitted. A new phylogenetic analysis of the large genus Plectranthus has also been prepared and will be submitted for publication shortly.

Our major taxonomic focus is now South East Asian Lamiaceae. Significant progress has been made towards an update of the Lamiaceae account for Flora Malesiana and treatments of the family for the Tree Flora of Sabah and Sarawak, Flora of Peninsular Malaysia and Flora of Thailand: accounts will include c. 400 species treatments and preliminary conservation assessments. Taxonomic revisions of Teijsmanniodendron (de Kok 2009), Bornean Callicarpa (Bramley, 2009) and Malesian Vitex (de Kok, 2007, 2008) have been published; revisions of Malesian Clerodendrum, Premna, Gmelina and the remaining Malesian Callicarpa, are in press. The confusing generic limits of Vitex and allies were clarified in a phylogenetic analysis (Bramley, Forest & de Kok, 2009). As part of this process, we have conducted fieldwork in Thailand, Malaysia, Indonesia and Vietnam and have developed successful working relationships with our counterparts, some of whom are contributing to flora accounts.

The World Checklist of Lamiaceae and Verbenaceae, covering 7,550 species of Lamiaceae and 1005 Verbenaceae, provides information on accepted scientific names, synonyms and distributions. The Checklist was originally compiled by Rafaël Govaerts and was primarily literature-based. Family and generic delimitation reflects circumscriptions followed in Harley et al. (2004). The Checklist was made accessible via RBG Kew’s website at the end of January 2006 and is now maintained as part of the World Checklist of Selected Plant Families (www.kew.org/wcsp). An online interactive key to genera of Lamiaceae (www.kew.org/herbarium/keys/lamiales) was produced with Nina Davies, a college-based sandwich course student, who spent one year working with the Lamiaceae Team. This is a user friendly identification tool aimed at professionals and amateurs; handy factsheets provide description, distribution, and nomenclatural information about each genus of Lamiaceae, as well as images of living plants and herbarium specimens.

The Salvia border continues to be a major attraction at Kew, providing a beautiful array of colorful flowers throughout the summer and into the autumn. Plants in the border have been sampled as part of the Salvia chemistry project. Of these Salvia species, 76 were screened for both antibacterial activity and antibacterial synergy with the quinolone antibiotic ciprofloxacin. Antibacterial activity was observed with many species, but antibacterial synergy occurred with just one species, Salvia greggii,and the active compound was subsequently identified.

Lamiaceae species are often used traditionally as medicines and insect repellents and insecticides. Over the last five years, we have investigated over 150 species of Lamiaceae in an array of assays to identify which compounds modulate plant-insect interactions as well as those that have pharmacological activities that could be used as cosmetics or medicines. Chemical profiles of over 180 Lamiaceae specimens have been determined for the purposes of quality control and authentication. Gas chromatography/mass spectrometry was used to investigate authenticity and quality of Melissa officinalis and Lavandula angustifolia oils tested for their pharmacological profiles, with a focus on ligand-gated channels relevant to potential alleviation of agitation in dementia. This analytical method was then used to monitor the chemical stability of an M. officinalis formulation, investigated in a double-blind, placebo-controlled, randomised trial (sponsored by the Alzheimer’s Society) as a treatment for agitation in Alzheimer’s disease patients. Over 50 species of Lamiaceae from the Queens Garden at Kew were also screened for inhibition of the immunological drug target calcineurin to aid understanding of mode of action reputed to be anti-inflammatory. Teucrium chamaedrys and Nepeta cataria were both found to be active. Phenylpropanoid compounds were detected in both species, which were predominantly selective for basal un-activated calcineurin as opposed to calmodulin-activated enzyme.
The Team has supervised three Ph.D. students over the period, co-supervised with Reading University, Birkbeck College and Khon Kaen University, Thailand.

Looking to the future

A greater understanding of relationships has shown that Verbenaceae are not the most closely related family to Lamiaceae. Verbenaceae is largely a temperate South American group, an area outside the focus of RBG Kew’s regional teams. Due to these factors, the Lamiaceae Team investigated how best to focus its expertise and collection based research within Lamiales to create the biggest impact. Maintaining a research focus on tropical Lamiaceae complements other research groups in Europe and the US. Taxonomic research will continue to focus on the problematic subfamily Viticoideae, large tropical genera and floristic accounts to see the completion of the family for Flora Malesiana and Flora of Thailand.
A new focus for the Lamiaceae Team will be Gesneriaceae. Strengthening existing collaboration with the Royal Botanic Garden, Edinburgh, and US institutes, the Lamiaceae Team will coordinate a project on the large genus Cyrtandra, a taxonomically problematic group containing at least 600 species from Southeast Asia through the Pacific to the Hawaiian Islands. The study will take an integrated approach to furthering our knowledge of the genus through taxonomic and phylogenetic study, continuingwork that has already shown Cyrtandra to be a model genus for answering critical biological questions. A key output will be the account of the genus of Flora Malesiana (c. 400 species) and a scratchpad that will bring together information on nomenclature, species distributions, preliminary conservation assessments and descriptions and identification keys in a single, readily available place.

The Lamiaceae Team primarily contributes to the Breathing Planet Programme strategies 1, 2, 4 and 7 (the last through the Salvia and Lavandula borders at Kew).

Conferences and workshops

8th International Flora Malesiana Symposium, 23-27TH August 2010, Singapore Botanic Gardens

Oral presentations:

Bramley, G.L.C. Distribution patterns in Malesian Callicarpa (Lamiaceae).
De Kok, R.P.J. Premna, a surprisingly interesting genus.
Sengun, S. The Vitex trifolia complex: a truly complex group of plants.
Wearn, J.A. & Mabberley, D.J. Clerodendrum confusion – redefinition and new perspectives for a large labiate genus

Poster presentation:

Walsingham, L. & Bramley, G.L.C. A revision of Sphenodesme (Lamiaceae) for Flora Malesiana.
60th Congreso Nacional de Botanica, 23rd June – 3rd July 2009, Feira de Santana, Brazil
Lamiaceae symposium, organised by R.M. Harley, A.J. Paton and T. Regina Santos Silva.

Oral presentations:

Bramley, G.L.C. & de Kok, R.P.J. Re-defining Lamiaceae subfamily Viticoideae and allied genera: progress and problems.
Harley, R.M. Diversity and distribution of Hyptidinae, with special reference to Brazil.
Mabberley, D.J. ‘Picking up the pieces’: the dismemberment of Clerodendrum (Ajugoideae).
Paton, A.J. Systematics of tribe Ocimeae: status and prospects.

Workshops:

Bramley, G.L.C.: Demonstration and launch of the Interactive Key to the Genera of Lamiaceae
Paton, A.J.: Lamiaceae checklist

First International Lavender Conference, Cambridge 9-11th September 2009
Simmonds, M.S.J. Overview of the biological activity of Lavandula.
Paton, A.J. Lavandula and the Lamiaceae.
7th International Flora Malesiana Symposium, 17-22 June 2007, Leiden, The Netherlands

Oral presentations:

Bramley, G.L.C. Callicarpa (Lamiaceae) in Malesia: there’s more than just one!
de Kok, R.P.J., Go, R. & Bramley, G.L.C. Reassessing Vitex and Teijsmanniodendron (Lamiaceae) in Southeast Asia.

International Policies

The Lamiaceae Team contributes to GSPC objectives I (targets 1-3), II (targets 4,5,9), IIII (targets 12, 13), IV (target 14), V (targets 15, 16).

Science Team Leaders: Gemma Bramley, Alan Paton